There are efforts to make this happen in the us starting locally and working up. The states are left to decide how they implement elections on their own with a couple of exceptions. There is a tragedy of the commons aspect to it though, as if some states adopt proportional representation but not others the ones that do not adopt it gain advantage. Ranked choice voting is taking hold much faster than pr in the us, and it is pretty slow too. It can happen though. Both are viewed as being left leaning, which doesn't really make sense to me.