RawSteelUT: Unfortunately, this bit of logic and reason is going to be wasted on this forum. Let them go reee, get it out of their system.
You don't get it at all for eternity, do you? To you is "just a quarrel of angry birds," which you like to out-wait under the rock.
The room is in flames made by the publisher, you drink the tea, "This is Fine," you say, forgetting that accepting the flames instead of calling firefighters is what leaves people with ashes. Imagine, you go to a pizzeria but what you get is suddenly a whale carcass! Will you be OK with this, will you chew the bones?
This could be not an issue in my view if the publisher's "bright minds" have made the installation of the launcher a separate shortcut (in the startup menu) with the "beware, it will install spyware" warning, or left it optional in the redist game folder without any shortcuts (add to the game description a note on that, no big deal), then made the older version available indefinitely or better yet made a new product entry separating the two as it should be, not stealing a product from the library that the people paid for.
On multiplayer, GOG has its API, games like "No Man's Sky" do have crossplay without apps like Epic Games. If the publisher wanted, possible to do cleanly.