While I disagree with your criteria, I agree with you in principal - it's not black and white, and we could do better as an industry (speaking as an online game developer) to set clearer expectations around what will happen and when it will happen.
I would happily and whole-heartedly support a bill that requires some sort of SLA/minimum guaranteed availability for licensed content to be presented along with the payment terms in plain english. Something like "By making this purchase, XCORP agrees to provide you with an ongoing and updated YGAME until at least DD-MMM-YYYY and after that point makes no guarantee for availability. This date may change but may not be moved earlier without your agreement".
Which is pretty much what we as developers negotiate with cloud providers, third party technology, etc. Note I'm not a lawyer, so please don't critique my wording here.
I think such disclaimer pop-ups would be the worst kind of GDPR banner style 'solution' to the problem. Copyright having an expiration was supposed to be a balance of the public interest and author rights. Copyright extension and DRM has absolutely smashed the scales. Once something leaves commercial relevance it should enter the public domain. In the case of software this pretty much requires source code.
