Budget alerts were the design decision made. You can set up your own infra to listen to budget alerts and cap your own costs. This is a feature that only makes sense to put in the customer's control because a general solution would work for no one. It's a great solution to the problem imo.
This is way too complicated for people who use AWS on a small scale. Maybe if they provided some template to implement that system in the first place?
Anyway, they should be able to protect people from an unexpected $1k charge. Once you deal with alerts triggering automatic infrastructure changes, $1k is likely a value you won't even notice.