Yes, there's the sense of being a custodian for the royal name, and you hand it on to your kids, like an heirloom, well, literally I guess.
You don't want to lose it.
But what if they did? It's then a short hop to Ms Nobody if a divorce then comes through, given they're married to millionaires. And it wasn't that long ago that everyone thought they were jolly nice sorts, maybe they still are but...