I think that's partly because that was the focus of the talk. I believe that Drew (for example) had a working prototype of Dropbox before applying to YC, and he

I think that's partly because that was the focus of the talk. I believe that Drew (for example) had a working prototype of Dropbox before applying to YC, and he'd been thinking about it for years. Then, after funding, it was quite a while (I think 6 months+) before the initial version was released. That's a lot of work on tech. I'd love to hear a talk on the tech journey of DropBox.