I'd better admit that I had the idea of the next monarch, Prince Charles (to distinguish him from our poster here!), possibly toying with the idea of being crowned in St Paul's, because of the greater space for a much larger congregation.
I also think of the amount of scaffolding that goes into building extra seating and galleries, and the amount of protection put into keeing effigies safe in the Abbey.
In this age of keen awareness of rare treasures, there could be a case put for moving away from the Abbey, for its own protection.