I saw an interesting suggestion that copyright should just be for a given period at a given cost of registration... say first 10 years as-is, but if you want it

I saw an interesting suggestion that copyright should just be for a given period at a given cost of registration... say first 10 years as-is, but if you want it longer, you pay X for N years, and it doubles each time you pay. I mean if Disney wants to pay $1B+ every few years to keep "Steamboat Willie" under copyright, let them. Eventually it will be cost prohibitive and enter the public domain.