This is an incredibly misleading link. Most of those are online-only games that have been shutdown (or the multiplayer part of the game has been), it's not at all the same as having a DRM that needs to reach a server for a purely solo experience.

Sure, but there are also single-player games on the list. You asked for a source that such a thing happens. The link proves that it does.

Again, it doesn't prove anything.

If you see the top of the table it says "Specifically games no longer listed as being available for sale through any means.".

It doesn't mean you can't play the game if you already acquired it...

I have Steam games that aren't sold anywhere anymore but I can still install and play them just fine.