True...that they all use NFC payment, but each payments are slightly different. Take Apple Pay and CurrentC, these are two completely different solution. Do you expect such fragmented mass is going to help mobile payment?
Second, Google, Apple, Samsung and all these mobile payment solution need support from all major banks. Do you think banks gonna support everyone? If bank bjng selective, then some population gonna be left out, this certainly does not help mobile payment strive.
All major company need creat a entity that handles mobile payment, so that everyone can use mobile payment. For plastic card, there is no technical barrier, every one can use a plastic card, no one is left out. Mobile Payment is diffetent, consumer need to choose which mobile payment solution, they need choose devices support that solution and banks need be on board. It is way to complicated for ordinary users.