No, they are.
The only thing we'll have left soon is cracked minecraft launchers and community-created authentication servers.
Thankfully, yggdrasil and Minecraft authentication is well-known, and well-documented, as well as the client-server protocol as well. I won't mention where because I fear Microsoft might take it down, but it is documented somewhere, and a copy of it as well as a functional 1.12 implementation has already been archived as well.
If Microsoft decides to do an Oculus Facebook with Minecraft and add a restrictive ToS and other things, we'll just spin up serve