Uncle Sam's country

The buy SIM, stick it in and top up option is hard to find.
Not much info out there, what I could find is: Prepaid SIM, bring your own unlocked phone: T-mobile,    PC Mag survey of pepaid SIM card deals in the US
Is this really the situation ? Many reports seem to say so:
It was a surprise to see that in the land of opportunity, the phone and SiM situation is pretty tight, hard to find prepaid for unlocked phones, everyone is herded onto a plan in some way and the big providers keep their customers on a tight leash.