If Napster was really pro-artist, they would have put a micropayment system in the Napster client from the beginning. But, as e-mails from the Napster founders have illustrated, they knew full well they were making piracy easier, not making it easier to fund the artists.
I'll say it again, if Napster had micropayments, I'd use it.
And hey, wouldn't it be cool if users could make some sort of commission for offering the hard drive space and bandwith needed to transfer the files? Not only that, the effort to rip the songs in the first place!
EVERYONE would use Napster if that was the case... :-)