I think a scaled cost would be more interesting, although the chances of it being implemented enough to test it anywhere is probably nil. E.g. you get 5 years f

I think a scaled cost would be more interesting, although the chances of it being implemented enough to test it anywhere is probably nil. E.g. you get 5 years for free without registration, to get another 5 years you must register and pay a small fee, for another 5 years you must pay 10x the previous fee, etc. Scaled in a way where it is relatively cheap to keep a copyright for 2-3 decades, but keeping one for much longer becomes financially prohibitive