I don’t think the point is that the people saying it at the time were stupid, it’s just interesting that people can come to completely wrong conclusions which seem reasonable at the time.
There was a time on HN where it actually made sense to bat a YC application back and forth, and to talk about what might make a more or less compelling one. It's long gone, and the people dunking on this comment have completely lost touch with what the original community was. I'm not saying that community was better (it was much more insular), but it was certainly more collegial.
† In fact, I think we now know it was literally correct, and YC had the same qualms, accepting Drew Houston just to get access to him and apparently hoping he'd find something better to work on.
As you can see by the success of Dropbox, point 1 wasn’t a real issue. That’s also the funniest point, because „why would anyone pay for XYZ, as a software engineer I can just do A, B, C, and D myself“ is such a common counterpoint which completely neglects that most customers aren’t going to do ABCD themselves because they don’t want to deal with it and don’t have the know how.
And point 3 probably can also be classified as wrong, at least Dropbox seems to make some amount of money.
Because to me it seems like he’s criticizing the product itself, not just the presentation.