I think it will take approximately 5-10 years. They will need 1-3 years for developing the project and the same time for implementing it.
Woow...
It looks like you are seeing the future. I don't know what is your basis for this but, to be honest, 5-10 years is not enough to completely dissolve physical and turn into digital transformation. In fact, many people are still don't know about crypto, don't even know how to use phones (esp for the oldies). And how this cashless mode of payment will be fair and comfortable for everyone?
I don't disclose any possibility to make it happen but it takes decades, or until such time that national banks won't print paper money anymore. But for now, we are just considering this as another option cause I know, once this pandemic will be over people will turn back into using fiat money again.
5-10 years? That is very short. Bitcoin or crypto has been here a decade and yet only small percentage of global population has the grasp of using it. Maybe in another 5-10 years time, the adoption will increase. But phasing out fiat money? that is very unlikely to happen. Just think of those people who are still unbanked up until today and those that have no connections with internet. So yes, it may take decades and decades before we will see high percentage of population that are into digital currency.