Even if they do stick with one game, it’s hard to keep up. My kid has stuck with Minecraft (when he’s not playing his favorite game: NFS Heat) and he always wants to play Minecraft with me, but every time asks me to join, he’s created a new World and started over, and everything I helped him build in the old world is gone.
I subscribed to a realm! We built in it for a while but then he didn’t like it anymore. Wanted to move on. Now I’m paying for a realm he doesn’t use.