It might be “trivial” but in my experience most engineers at these companies are too busy trying to look good in order to either survive the next cut (particularly egregious at Amazon) or get promoted, and fixing this does neither.
As Charlie Munger said: show me the incentive, and I’ll show you the outcome.
Apparently most of the AWS services are things that Amazon teams needed and built, which is why the UX and options for them are all over the place.
I’d attribute that checkbox to that rather than AWS evil.
They also just have 0 incentive it make it better. Third parties like vercel do it for them at a premium.