But they do have more investor money than 25k, don't they? Plus, proper incorporation serves your investors as well. Guess why YC ibsists in a Delaware corporation? From what I know, those are totally free of charge neither.

At the start? No, why would they? Raising money is usually something that makes sense after you build your mvp and all. If you really want an llc that's maybe $100 bucks. Otherwise cloud compute and stuff are near free at those scales and your own time isn't something you get paid for either.