I think what changed for me is that I got good enough to regularly interact with people at the "highest levels" of what I do. Teaching probably had some impact on me as well.
I still work hard and enjoy improving, but if I'm completely honest with myself, I'll never be as good as some of the people I regularly interact with. Their minds are gifts that no amount of hard work can compete against (especially because they're also incredibly productive... which in some sense is, I think, also a genetic gift. I need my 8 hours of sleep and can't consistently work more than 10 hour work weeks.).
Since having that realization, I've noticed that most people in my life who prefer the growth mindset happen to work in occupations where there isn't a lot of room for variation -- or where variation in productivity is almost completely explained by factors under your own control. E.g., factory work, truck driving, and the sort of healthcare occupations you can do straight out of high school. Or in one case, a software dev who puts in his 40 doing very standard C# LoB CRUD apps.
Figuring out that there's an essential difference between my environment and theirs was a huge relief -- it's not that I wasn't working hard enough (I definitely was), it's that the type of work I'm doing is much more sensitive to variation in natural ability.
Maybe ignorance is bliss when it comes to the growth mindset.
"The more you know, the more you know you don't know."
The less you know, the less you know you don't know.
Being a knowledge junkie, ignorance would be bliss. But once you know you can't easily go back and un-know.
You can be born super lucky to get, say, a 100 multiplier in playing the oboe, you will be considered "gifted" and you will rush past your peers, however all you have is a multiplier, if you put in 100 hours and somebody with a 1 multiplier puts in 20,000 they will become better than you despite your "gifts". But if somebody that has a 100 multiplier puts in 20,000 hours then they will reach levels that you could never ever reach due not having enough time in your life to do so.
On the other hand, unfortunately there are plenty of cases where you might get a 0.1, 0.01 or even 0.001 multiplier, and in those cases you can work hard as much as you want, but you will never ever become more than competent at whatever this is even after a lifelong pursuit. I am pretty sure for example I have a 0.01 multiplier at painting unfortunately.
In the end one always needs hard work, but there should be the understanding that due to how you are born, your hard work might not ever give you the level of performance you would like to have, and that's nobody's fault. This is also why the people that excel at something and go "it was all about hard work, you can do this too if you try really hard" do a great disservice to everybody else.
If you "try really hard" you cannot become an astronaut unless you are genetically lucky and have all the required physical attributes, same deal about becoming a world class anything.
It does feel like the only way not to get depressed is to tape/record yourself regularly at anything you do, always save some of your learning efforts (paintings, musical performances, woodworking things, ...)
I personally am lifelong learning playing the pipe organ, and midi record every single practice I do: when I feel bad about a perceived lack of progress, I play some midi files of six months ago or whenever and I am instantly reminded that yes, I am progressing slowly but I am progressing quite a bit. The only thing I personally have issues with is that no matter how well I learn a piece I will always make at least a couple of mistakes when playing it, I wish I could get a piece perfect but it seems that whatever my multiplier is for "perfection" it is a lot lower than the multiplier for "good enough"
I think most people can be decent at most things, certainly. Humans are (almost always) normally distributed, and odds are you're between 0.5 and 2 on most scales. If you want to run a 5k, or play guitar for fun, or make a website, your multiplier probably won't stop you.
But if you want to be the best, or you're choosing a goal where demand is short (astronauts, professional tubists, etc), you'd better think about your multiplier. There's a reason music schools are so viciously selective, and it's that hard work isn't going to get you a career unless you're somewhere up in that 100+ territory.
I'm pretty sure I'm down around .1 for music. I'm fairly tone deaf, my sense of rhythm is crappy, and I've never found any part of music intuitive. I've played some instruments, I don't regret it, but I'm certainly not going to go stake much of my time on being even middling-competent.
You touch on one thing that I think is a huge deal - people with big multipliers don't necessarily feel it. That top-notch musician knows they worked their ass off, but can't experience how they would have done with a worse multiplier. It's like listening to successful founders say that you should just focus on your idea and "it'll all work out in the end" - that's sample bias like no other.
I didn't get really skeptical about pure effort and growth mindset until I started working out how specific people learn. The gulfs in effort for different people on the same achievement are shocking, and this model is far better for understanding that.
Well, mine did :-D
After 3 years of practice, I could still not accurately do what a kid can do after 1 week, or someone who plays another instrument after 20 minutes.
It was time to throw in the towel and admit that there are hopeless cases and that I was one of them :-)
The worse thing is that I did not have great expectations when I started, since I don't have any interest and even dislike complex music. But I couldn't even reach my very very low expectations... By far... since 3 chords were 2 too many and the other one would never come at the right time :-D
But, I think the key realization is that whenever the incentives are strong enough, a lot of hard-working geniuses will be fighting for the prize. Hard-working geniuses are really hard to compete against, and if you don't realize that natural variation is a real thing, you can get discouraged pretty quickly.
Usually, those people are making disproportionate contributions to the world for comparably small rewards. Usually. We're lucky to have Einsteins and Bachs and Taos and an infinitude of less well-known but probably equally capable hard-working geniuses. I'm very grateful for hard-working geniuses who devote themselves to important problems! Some of them do apply themselves toward more secular ends, such as Gates. That's OK too, although the world takes care of gratefulness for me ;-)
It's just important to realize they exist if you ever get into a situation where you're regularly competing with them.
Google shows me nothing but out-of-context biology-textbook material, so I'll ask: what is the relevance here of "natural variation"?
I just meant "some people are smarter/more productive than others for reasons beyond either person's control at the time of measurement".
So it could be environmental factors (access to better support or higher quality educational experiences in early childhood). Or just genetic. I'm not positing any specific causes, just making a general observation that I find to be true of the world I see around me: especially at the highest levels, some people really are just smarter than others, and no amount of hard work could close the gap.
Some people find the innate ability mindset oppressive and saddening, and are greatly comforted by "you can do whatever you set yourself to!"
Other people find growth mindset oppressive, and greatly prefer "you can't be the next Gauss, so stop feeling bad about his achievements!"
None of which is a strictly relevant to what's true, of course. The answer there seems to be "lots of skill is inherited, skill plus effort is required to truly excel, but skill and effort are often interchangeable except at the highest levels".
But for whatever reason, I'm in the second camp with you on which narrative is depressing. A lot of growth mindset writing is almost physically uncomfortable for me. I appreciate the value of hard work, but believing that everyone is equally capable completely contradicts my life experience, and implies that 99.9% never fulfill our potential in even a single domain.