@aral not really, consider that kids don't usually have bank accounts and are fine with using cash. Why can't adult live that way?
Just that in case of banks even in small countries you have a choice of more than two, while with mobiles there are more than two options, but the two dominate so much, that no one cares about the others.
@aurisc4 Kids can live that way because they have parents with bank accounts.
So should you be able to live without using a bank? Yes. Is it practical to? Not really. Should it be legal to require either an Apple or Google phone to have a bank account? No.