Yeah, fair enough. It's more like it could be more fun, if you're obsessed with the field, and your advisor isn't terrible, and your program doesn't encourage cutthroat competition (by e.g. admitting more students than the faculty can realistically support), and you're willing and able to live a Spartan lifestyle (in particular, no financial dependents), and ...

I'm lucky in a lot of ways and I sometimes forget that.

I think your previous answer using the word "fun" was spot-on. I have a non-CS PhD that's not really related to what I do today. I would describe what I did previously as "fun"; despite the intensity and worse WLB than life in a big-tech company, you're ostensibly choosing projects that you and your adviser consider fun. In bigtech, you have a lot less freedom to choose what to do. Seriously, if you don't consider your PhD fun, you should just drop out now; if you plan on just going to industry later to make money (esp as a SWE), there's no reason to get a PhD.

It’s interesting, of course, that a similar set of caveats apply to working for early-stage startups - not that this forum would attack anyone for calling working for one fun.