I think the answer is that the pain wasn't enough in the US to encourage the kind of innovation you saw in Africa. The marginal benefit of paying with your phon

I think the answer is that the pain wasn't enough in the US to encourage the kind of innovation you saw in Africa. The marginal benefit of paying with your phone instead of card in your wallet is actually pretty small for most Americans, and much of it can only can be realized until you can leave your wallet at home. Similarly for other innovations where the incumbent was "good enough," ubiquitous, and already built.