Yes, I also think that it could be achieved. The problem as everywhere is the adoption. When two or three big companies would stand behind it, it could be easily implemented and I really would like to see a scheme like that.

There are of course some questions, that also would need to be solved. For example: What if an other person has access to my computer -- than I still would need some kind of master-password that had to be remember-able. Also there must be methods, to transfer my keys to an other computer or to "copy" for example onto mobile devices.

The example of the SIM-card for banking just shows, that the "big security" is really a hard problem. Two-factor is one idea, but it is always a game where the attackers are hunting the defenders (or vice versa).