At the very least I would also accept a DRM free copy being provided to everyone who had purchased it (e.g. at least one year or so to download it), and in fail

At the very least I would also accept a DRM free copy being provided to everyone who had purchased it (e.g. at least one year or so to download it), and in failure to do that it becomes public domain. Anything less and we basically just end up with the classic xkcd situation https://xkcd.com/488/ https://xkcd.com/488/