It's not clear to me why he's closing shop other than he's "moving on to whatever else catches his eye." But to go to his site he boldly shows that the museum is closed "forever" and no further explanation is offered. Doesn't that sound a little cold like there's some spite, disappointment or obstacle behind it?
He was supposedly a devoted collector and expert, passionately searching the world to recover and meticulously restore one-of-a-kind pieces. Can someone just walk away from that? Even if it's just to cash in, I wouldn't begrudge him that. But no farewell or thank-yous seems odd. It's a unique and important collection.