If you only read the headline, GOG is still selling both games until December 13th. Now, I have to weigh the calculus: do I buy the games just because, knowing there is basically zero chance I boot them up? What if that was Blizzard's end game -to drive scarcity?
like other game companies (cough Nintendo) their old library is viewed as direct competition with their current set of games/subscription products. also wotmrth remembering that Blizzard is now a Microsoft property.
That's nothing special to game companies. All entertainment companies are the same way. That's why they push for longer and longer copyrights. Copyright is what protects Disney from having to compete with its own past work.