Kingdom Hearts 1 was released before the merger, and KH2 was released shortly after the merger. Short enough that you could argue the merger had no major impact on its development.
And sure enough, there's been pretty much nothing about KH3, just a bunch of "side" games.
Yes, it's free.
So there's no ongoing benefit to Blizzard keeping the Starcraft 2 servers going after about a year when the sales start to trail off.
What is it like TWELVE YEARS now and people are still playing Starcraft against one another via LAN? You think there's any chance that Blizzard is going to still be running a Starcraft 2 server in 2022?
Sometimes, being a fan of a product to the extent that you'd buy it no matter what works against your own best interest.
The ORIGINAL Diablo is still playable on Battle.net, as is Diablo II, Starcraft, Warcraft, etc. Blizzard isn't one to drop their servers when the game gets old.
Those who can, do; those who can't, simulate.