Free trials are an essential for the reasons you describe - but it doesn’t mean it has to be free forever - just for long enough to make an honest evaluation. 30 days is the norm, and that seems fair to me.
AWS (and generally all *aaS providers) free tier(s) are enough to experiment with, and get a feel for, but are limited enough that using them in any meaningful way is very difficult without incurring cost.
Surely you can appreciate that "time" is not the only commodity that can be meaningfully (and reasonably) limited?
That said, much (but not all) of the AWS "Free Tier" is really just a 12-month free trial. Only a small percentage of the offerings are truly longterm freemium.
Surely you can appreciate that "time" is not the only commodity that can be meaningfully (and reasonably) limited?