But this theoretical card would have no advantages over currently existing flash cards, and especially not over harddrive based players. Being limited to listening to only a single (or a couple) of albums at a time is a thing of the past thanks to the harddrive players, and nobody will want to go back at this point.
I am not talking about people like myself - I don't even own an MP3 player. But I still think it's the tech-savvy people who are needed for a new format to take off - if they don't take it up first, nobody will follow. The average consumer isn't interested in a new format no matter what it is, so you need the people who like new stuff to take it up first and turn it into an existing format so the others can follow.