I really wish the study matched the headline. It should be 'most classic video games are commercially unavailable' To their credit, they don't try to hide it, but the sentiment in the headline is the actual problem, in my mind.

I'm less concerned about a gameboy game that you can't buy, but you can easily play via emulators or the physical cartridges, which still exist (for now), than I am with the class of games that are truly gone/unplayable.

Your online only games primarily fall into this bag, but without something like an internet archive or something similar to preserve them, we're in danger of losing the digital copies of old games as well.

Personally, I'd like to see the study expanded and then some sort of index that tracks true loss of media over time.