It really is. Arguably the most famous example among HN readers was BrandonM’s comment[0] on Dropbox’s launch thread. Was he correct that you can built it trivially using 2007 software? Sure, if you had the correct mix of specialized knowledge of the software and networking. Dropbox was not a novel idea, but that’s now where it value was; the value proposition relied 100% on its UX.

If MSFT and Apple each shipped a Dropbox competitor that was highly integrated, available, and pushed flagship software suits to adopt it as well within a year, would Dropbox had become as large as it did? I would guess not. It would likely be a downgrade from what Dropbox offered (the separate ecosystems staying bifurcated comes to mind), but a zero install solution would be the only thing that could make it easier.

[0]: https://news.ycombinator.com/item?id=9224

This is like the whole reason we use slack everywhere lol