I can't really imagine what I'd do. My main other hobby is miniature wargames, where I go to a game store and meet up with opponents to play. It's sometimes problematic due to other people's schedules, what games I want to play vs. what games other people want to play, time for assembly and painting models, etc... Pinball is my hobby I can do anytime at home with no scheduling issues which makes my wife happier. Further, my 11 year old special needs son and I play pinball together and he's never had any interest in any of my other hobbies so it's the only one I can share with him and that's worth a lot to me.
I can't imagine anything I could do with a big pile of money that could come close to replacing these qualities in my life. I guess I could buy DIFFERENT pinballs?