But it's also the case that if they did implement hard limits of some sort, you'd be reading blog posts about how AWS destroyed my project just when it was going big because someone stuck a circuit breaker foot gun in some corner and everything stopped working properly when usage spiked.
I do think there should probably be a hard circuit breaker. It should be simple and therefore inflexible. And it should come with a big warning sign. Still people will get burned because someone will set it, a project grows, and one day it goes off.