That's the story of the people who are mad at him on Twitter. It's not what he says, he says he's happy and has kept saying things like how getting out of Mojang was the best thing he did.
It seems to me he's reasonably happy, especially considering his circumstances were far from happy before Minecraft - his parents were ex-addicts, he had himself dropped out of school, his father had a mood disorder and relapsed into drug use and killed himself just weeks after the first big Minecon.
My point is that he's in a shared melodramatic phase. It seems bad now, no doubt. But time heals all wounds. He'll find his friends again. He'll realize that Twitter isn't the right forum for posting batshit crazy stuff if you're sensitive to criticism. He'll repair things. He'll find his peace. Or he'll go insane. I'm hoping the former as a fellow human.
I didn't say it does, but the clear fact of the matter is that there is literally no evidence that being rich leads to being miserable.
People saying "money doesn't buy happiness" don't realise that money doesn't bring unhappiness either. You can't use that statement for asserting that some rich person must be unhappy.
That's not what he said, and no, Notch didn't do anything wrong here. He's referring to everything about current day Notch(sad, alone, transphobe in billion $ mansion that panders to the right on Twitter all day and hasn't had anything creatively interesting to say since 2015).