I'm curious why you think "you own this game from our store front in perpetuity" is required to rival the ownership of physical media. If I buy a game from Walmart am I allowed to go back there when my disc was damaged and get a new one? Of course not.

GOG allows you to download and backup the installers of the games themselves, if you back these up well you can use those installers in perpetuity to get your game back on any machine in the future.

The point of this is not to be a direct undoing of Sony's decision. This about preservation, one of GOG's big missions. The games listed as having this in the article are old games who already had physical media, and as part of the preservation effort they are trying to preserve the context of the physical media which is a very significant aspect of the game.