I think this kind of event - the super rich paying for the most famous entertainers in the world to appear at their party - has become a lot more common over the past few years. I suspect this is tied up with the phenomenon of live gigs and concerts becoming more of a focus for artists and ensembles.
As record sales decline it's becoming easier and simpler to earn money from touring than record sales, even to the extent that some music is being given away for free to tempt people pay for gigs. As this happens and everyone listens to (essentially) all the music they want for free whilst also becoming more willing to pay money for gigs this is a way for the super rich to assert their wealth and power.
Getting such famous bands to come and play for them personally shows that they are superior to the rest of us and gives them instant cachet. This is just an extension of the move we're seeing towards live experiences to balance the increasing amount of time we spend online.
Red Hot Chili Peppers Play Abramovich Party