> Why bother with exponentially increasing costs? Even a token fee would ensure that copyright expires on abandoned/orphaned works.

A token fee would do that for abandoned works, but it wouldn't do it for works which weren't being actively used but which the owner also didn't want others to use -- an escalating fee would be better than a token fee to discourage such buried works.

You need increasing fees to prevent big business from automatically renewing all the time. Make them think if they want to renew it all. Otherwise they'll decide the just renew it all.