If you have a product that works and makes a good profit, and you can maintain it with 10 people and extend it with 5 more, sometimes that just is the company.
In this context I think it is important to note that Ycombinator was founded in 2005. For the majority of its existence, and the general hype of tech startups, money was incredibly cheap. Now that the gears are switching, a lot of the advice given to startup founders does not work as well anymore.