We constantly underestimate the rate of change brought about by new technologies. In the US, that rate of change is slowed somewhat by existing infrastructure like the proliferation of credit card systems and our societies easy access to credit cards. Because of this, I think we'll lag behind the rest of the world in this movement. When it does happen, the change will be swift and will seemingly happen "overnight." Case in point, China went from 99.9% cash to 99% cashless using QR codes in less than 3 years: https://www.nytimes.com/2017/07/16/business/china-cash-smartphone-payments.html