[Kwpolska]

They've had two decades to figure it out. For EC2, they could shut down the instance but keep storage and public IPs. It shouldn't be too hard to estimate when the instance has to be stopped to end up with charges below the hard limit.

[cdchn]

Now multiply the logic required by multiple cost factors across hundreds of services.

[lucianbr]

Imagine how impossible it is to actually build those services, with all their logic, if just this added logic is impossible :)

[cdchn]

I didn't say it was impossible or even intractable. Its simply not as easy as everyone "why don't they justs."