I think the assumption is that only the most colossal implosions happen in the first 6mo after YC. It's much easier for 2-3 people plus 1-2 hires to burn through most of $80k in 6mo after YC, vs. 150k. Figure founders consume $3-4k/mo each, and hires cost $10-15k, and you spend $20-30k on corp/legal/etc.
> it sometimes caused messy disputes in the unsuccessful ones.
I can't imagine a dispute that would occur at 150k but not at 80, except maybe of the cut-and-run variety, but the same could be said of any dollar amounts - you need to know when to cut your losses.
The dispute happens after some of the money is burned off. Only very exceptional people get divorced during their honeymoon. Assuming a constant burn rate, there's much less money left when you start with a smaller pile.
(and, virtually anyone who can get into YC is passing on a $10-15k/mo income opportunity by just getting a job somewhere. Fighting for 1-2 mo of wages makes less sense than fighting for 6-12. The dispute would happen anyway, but it's not worth fighting if there's only a small balance left.)
