I'd extend it to all copyright but instead of "active development" make it a nominal fee every 10 years, so anyone that doesn't mind their work becoming public domain 10, 20, 30, etc years later can easily let it go.
Most IP owners would pay the tiny fee just to hold onto IP rights and do absolutely nothing with it. If I were designing this hypothetical legislation I'd make it 10 years without a release that works on new hardware and the copyright is lost. This would at least incentivise the owners to do remasters just to hold onto the IP, something that would make them a few bucks anyway.
