Scratched discs can be polished, pretty much restoring them to as-new condition, and the lifetime of Blu-ray media, even recordables, is pretty impressive, as in: longer than yours or mine.
Addressing the core of your question: in my opinion, the value of abandoned games is limited: playing them is usually no fun whatsoever, if only because of the quality-of-life being very-noticeably substandard due to later innovations.
So, a couple of (reproducibly archivable) playthrough recordings may suffice for most purposes. That being said, I do think publishers should be pushed to open-source their games upon reaching end-of-life. But given that a lot of dependencies tend to be licensed, as is some (or even most) artwork, that push should be rather gentle.
The main point of campaigns like "Stop Killing Games" should be addressed through regular consumer protection: if the game you bought becomes unplayable in 2 years or less, there should be a refund. But beyond that, I'm afraid goodwill is the only way forward, not legislation.
And I'm saying this as someone who still has several playable PSP Minidiscs, alas never plays them anymore (except Loco Roco, once a year), because, well, they're no fun anymore