"The downside of disabling active resources is huge. It would mean a catastrophic interruption to the customers application exactly when its the most popular/active."
Lol what ... this is exactly what happens any time you hit a rate limit on any AWS service. The customers application is "catastrophically interrupted" during its most popular/active period.
The only difference is in that case, it suits AWS to do that whereas in the case of respecting a billing limit, it doesn't.
If you hit a rate limit, the marginal portion of requests exceeding that limit is dropped: if you plot the requests, the graph gets clipped. Bad, but not catastrophic.
If you hit a billing limit, everything beyond that point is dropped, and the graph of requests plunges to zero. You're effectively hard down in prod.
And for some companies/individuals, if you keep charging then THEY will plunge to a large negative debt. It's not even zero, it's a lot worse than that.
Lol what ... this is exactly what happens any time you hit a rate limit on any AWS service. The customers application is "catastrophically interrupted" during its most popular/active period.
The only difference is in that case, it suits AWS to do that whereas in the case of respecting a billing limit, it doesn't.