Counter-Strike: Global Offensive was a game running all of these things (matchmaking, skins, anticheat ...). After Counter-Strike 2 was released, the servers for CS:GO were shut down. Yet, the game remains mostly playable. Sure, the skins no longer work and there's no official matchmaking, but third parties have stepped up. That's because Valve released (and have always released) server software.
I find this argument quite bad. It was done in the past and it's still being done today. There's nothing preventing any company from doing it except for a combination of laziness and greed.
This is such an overstated issue. There's not really that many MMOs. It's hard to say, but I would estimate that there are ~600-1000 MMOs total. Many of them are quite simple (like Club Penguin, MapleStory, ...) or already have third party servers running (WoW, City Of Heroes, ...).
Also, your example doesn't really make sense. First, no one is arguing that companies should right now go revive all past MMOs. This is something that would affect future products.
Additionally, why are you making a sequel to a product that already failed?
Yeah I remember this argument from decades ago where people claimed that WoW required specialized hardware to run that would be far out of reach of community server operators. What a bunch of bs that turned out to be.
I find this argument quite bad. It was done in the past and it's still being done today. There's nothing preventing any company from doing it except for a combination of laziness and greed.