Explain the mechanism. How do I know this organization made this much money and that the amount I'm being paid is fair in regards to their profits? How can this code track all the money the company is making? It's not like they're being paid with their tokens.
And for minority of projects where indeed they're expected to be paid using their own token, how do I know the company owners don't run away with all the money they raised? Because this is exactly what happened with 99.99% of ICOs created on Ethereum. Now, of course scams happen in the traditional financial system too, but not to the same extent, because there's an enforcement mechanism in place. So, following your example, what stops a YC company from declaring bankruptcy and spending all the money on things founders want for themselves? Well, an investigation may be launched: founders are known, they can be found, prosecuted and sentenced. With tokens issued online, where you may not even have a company registered or have a company registered in some obscure jurisdiction, there is very little incentive NOT to steal the money. And, once again, that's exactly what happened during the ICO craze, which Ethereum is directly responsible for. A lot of people lost a lot of money funding scammers - and nobody blinks an eye!
I don't argue that everything has to exist within the traditional financial system. On the contrary. But in order to provide real value and allow investors to have some level of certainty that at least their money won't be outright stolen, the solution MUST include an enforcement or incentive mechanism strong enough to deter scammers.