I partially agree with a slight modification. I write a lot of free software / open source software. This relies on copyright of course, to enforce the freedoms. I don't want an onerous registration environment, but if it was "copyright terms to 4 years after last publication without registration" but registration with a fee after that. So if I continue to make the software, it gets the copyright and if I get bored, it turns into PD - and that's fine.