The opposite problem when you do set low limits by default is that you constantly have to submit tickets to AWS to ask for service limit increases.

How is AWS suppose to know whether you want to immediately scale or not?

And before July of this year, there was no such thing as a “free tier AWS account”. There were services that allowed certain amount free.

Ask? This is not some impossible problem.

Yes, there is a UX challenge to be solved.

But also, doing so is well within the capabilities of a company like Amazon.

They simply have no incentive to help out since there is less money to be made by making it easier to spend less money. And, purely capitalistically, if you have to pick between a potential bug or misconfiguration that causes extra spending you can walk back with customer support, and a bug or misconfiguration that results in extra downtime for your 7+ figure customers, you pick the latter.

Their choice makes sense for their bottom line.

It's still bad UX for many users.

But as of July 15th of this year, there is actually a “free tier” that won’t let you spend over $200.

Before there were services with a free tier.