There is going to be an element of affordability. I doubt someone worth $1bn would spend it all on art but maybe they would spend $10m or if you prefer the growth of $1bn invested in SPX for a month. So a month's "work". A bit like $10k to many of us (I bet many of us have $10k of furniture)... which seems rediculous to someone earning $50k/y. It's all relative.