Usually you had he option at least. Either fork up full price for unlocked phone, or take the subsidized monthly rental of phone with a locked SIM.
And while the second option does lock you into one operator for 12-24 months you still had the choice of which operator to tie yourself to, I don't think I ever saw a phone model only available on single provider.
Finally no matter which operator you chose you can still call people from other operators, even if they initially tried very hard to make this less pleasurable by allowing free texts and minutes within the operator.
Then again, this was never the case in the EU, where bundling handsets with a GSM subscription was banned.
But yes, we don’t have to imagine - and the change certainly didn’t come out of the goodness of the carrier’s hearts!