Compare with the UK. We got credit cards in 1966. Not sure if they had mag stripe, but magstripe ATMs were in use from 1972. And magstripe continued as the primary method till 1997, when Chip & Pin started being introduced. Chip & Pin was in all merchants by the mid 2000s. So we had at least 25 years of "inertia" with magstripe, but it didn't stop us adopting Chip & Pin reasonably promptly.
Look at another area where the USA has been slow or incapable of adopting a standard - metric measures. Other countries had imperial measures for longer than the USA has existed, and yet managed to metricate. So it's not to do with inertia.
I think it's more to do with the culture. The conservatism, the feeling of "no one's going to tell me what to do, the distrust of government and public organisations, and "states rights" that makes any national implementation of a new standard hard to get through.