EU already have markings for lots of things, like how efficient a dishwasher is.

I think a reasonable middle ground here is to just have EU mandate something similar for games. To receive an A rating the game has to be installable and playable fully offline, for example, and so on.

They could allow for publishers to guarantee a minimum support period, with full refunds guaranteed if the publisher does not honor that. So an E rating may be a game that's guaranteed playable for 2 years and requires online connection to play.

Then those who purchase can make informed decisions. Do I want to buy this game with a rating that signals the game may stop working at any point the publisher decides?