I like it. If the publisher no longer sells/supports the full game as purchased, then they no longer to get to complain about people pirating it.
I don't like instantly throwing it public domain, that's the wrong license to use. I think Creative Common CC BY-NC-SA would be more appropriate. (Credit the original, no commercial use, and any modified/redistributed version must follow same license).
This will prevent xbox from taking all the old PlayStation games, stealing an emulator, and selling them under game pass to people that don't know those games are freely available.
I'd also add the game must be available as an individual 1-time purchase. If it's only available as a bundle or subscription service (like game pass), that doesn't count.