Earlier quoted context omitted.
Given the lack of details, my guess is that your role at those startups is wildly different from your role at the middle-sized company and also that these aren't necessarily comparable companies outside of size and age. 3 is also a stupidly small sample size for what it's worth.
You're moving the goalposts, but keep on digging I guess. I suppose your anecdotal and theoretical stories trump Tracy's lived ones and mine as well. No reason to continue this discussion.
> Being at a startup is hard in a way that is almost indescribable to anyone who hasn’t experienced it.
Because this simply isn't true. The point is also not that my experience trumps yours - the point is that this isn't generalizable and you're not comparing apples to apples.
Being at a startup doesn't have to be hard, at any level. And you and Tracy are certainly ascribing difficulties that arise from having responsibilities that are at times beyond your own capabilities and being extremely emotionally invested in the success of the company to being at a startup.