>most businesses do far more than you can see from the outside

It’s enough that they made it into YC to conclude that there is a lot more going inside.

They filled out an application and had to have many milestones hit before they were accepted...

Regarding focusing on a niche it was a lesson I learned when I was filtering startups for investments I wrote about about my lesson before and how dumb I felt for passing on startups because they were too niche https://news.ycombinator.com/item?id=22507122