The idea isn't that you go for years on the YC 150k. For most YC startups, the idea is that the social proof of getting through YC buys you access to the market for syndicated convertible debt rounds, which, while talked about extensively on HN, are not all that easy for first-time founders to access without YC's help.

So really, YC is giving you some money to get through demo day, at which point you'll raise real "runway" money from seed funders.

There's a cohort of YC founders that only do YC (or, at least, rely on YC's money for a long time before raising further); those companies get to break-even cash flow quickly and often aren't (or aren't yet) on the "shoot the moon" trajectory VCs are looking for. But those companies aren't made or broken by YC's decision to "fund" them.

It’s supposed to be like 4 ramen-years.