To me a "hacker" is someone too busy building things to get caught up in the semantics of why and how. Richard Stallman , for example, is no longer a hacker. He's too caught up in the "why" of open source software.
"The money problem" as pg calls it, is a significant barrier to being a hacker. Solve the money problem and you can work on whatever problems you want without worrying about why and how.
YCombinator seems to be aptly named. It is an attempt to solve the problem of solving problems. That is why it is the ultimate hack.