I thought the Wait but Why article made a point of calling that out. It didn't come across as blaming Lucy for her delusions, saying "she has _been told_ all her life that 'she's special'".
"Been told" seems to put the blame for that squarely on those doing the telling.
Setting aside the expectations of "you are special and can be anything you want to be" from parents there is also the "the world around you is crafted to a degree that previous generations didn't deal with."
Recognizing that part of it is also important. If you compare yourself to influencers and expect to be able to live a life like them, you will likely be unhappy. Correspondingly, if you compare yourself to the crafted image of your peers all the time, you may feel that you're not doing as well as they are.
That part isn't a millennial issue but rather a "everyone who uses social media to compare or boast about their current social situations."
While this may be true for some people, it's not all roses in tech. I know this may not be your intended thesis, but I think it's worth pointing out some things that many people in high paying careers find out (not just tech, lawyers, business pros, ect.)... just to add to your point:
1. You're not going to have ANY time to relax, if you're trying to really get ahead, and take care of chores, let alone hobbies (which can even feel like chores if you like relax time)
2. Even if you don't care about advancing your career, or making money, there's a good chance you will feel like there's no other option... it's up or out
3. You may not find a partner, or at least a good supportive one, which makes some of these things easier (helping around the house, providing an anchor for an uncertain career)
4. Even if you find a good partner, things can change. It can make things even worse, due to heartbreak, or the pressures of living with someone you don't get along with; or you can lose your kids and/or be stuck with a big bill for your hardship.
5. There's a good chance you will grow apart from your friends. There's a lot of reasons for this, work, family, etc. It can be hard to find time in the best of cases
6. There's a pretty good chance you spend all of your money, or else you won't have the lifestyle you're expecting.
7. Health problems. They can start pretty early in adulthood, make it hard to feel comfortable, and end relationships / careers.
Just to add to your point: Even with "the career" things can wind up being pretty bleak. I have a lot going for me, but I don't live that crazy a lifestyle, own a house, etc. I suffer from some of these problems in varying degrees.
While some of the above is unavoidable, and has always been (eg. health). Other things seem fairly new. Like people with high paying jobs not owning houses, or having to choose between that, travel, etc.
Social networks are at an all time low point. Not for everyone, but it's been a growing trend.
I don't think that owning a house, occasionally traveling, with a supportive partner, while spending time with your friends, and having a few hobbies is "unreasonably high" for someone in a high paying career.
I'm not saying these things are unattainable, and it is asking quite a lot. However even if you play your cards well in life, you can easily end up falling very, very short.
Yes, it's easy to get unrealistic expectations from social media. But that's not the point of the article, for anyone tempted to click and read.