It was too much pressure at the top, though, and he sold the project to Microsoft and became a billionaire; but what that actually meant is that Microsoft took it over entirely, and he was nothing. He didn't even get the position of "esteemed creative inventor who now only occasionally provides creative direction instead of being responsible for every last thing", that some people get when they sell their projects to faceless behemoths.
He had a further fall from grace in that the public didn't like his stated values on social media, and Microsoft took the opportunity to completely erase him from Minecraft - removed all mention of his name, and he's not invited to anything.
So now he sits alone in his mansion and cries himself to sleep, because while "never work again" money is nice to have, he'd rather have the kudos and recognition of being the creator of a much-loved game. And that's the one thing he can't have any more.