Then the startup has to ramp up a hiring pipeline to backfill or dump the work onto someone else. Either way they won't get what they want.

A startup that is firing engineers on the spot who dare to disagree probably won't last much longer anyway. Best of luck with their "critical" deadline then...?

I was worried about getting fired at these sort of places until I saw how they behaved when I quit a few of them.

Or you just miss promotions, raises, bonuses because you didn't do enough, "moderate impact"