Instead, people are apparently suing them because Microsoft banned gun mods.
America in a nutshell.
My partner and I are each on our second copy because at some point it was just not worth the hassle of recovering our old accounts.
If you bought the game back in the Notch-owned Mojang days, you have a license guaranteeing your right to access all future Minecraft versions. It's a pretty open-and-shut case.
I'm pretty sure you have literal years to migrate. I suspect you still can if you contact their support.
For an organization of Microsoft’s size, to be so incompetent at migrating accounts was a choice. If their underlying system was incapable of linking the product to my account, they could have just emailed brand new codes to everyone registered with the “lifetime” mojang entitlement.
I made a hacked version of the old launcher after that and now a couple friends and colleagues and I run a custom server and play on that occasionally.