They kept the titles, public purse and anything else they could....

They kept the titles, public purse and anything else they could. Don't want the hassle just the bucks. If they really didn't want the advantages they should just go and be Mr & Mrs Windsor.
Their offspring will become like most of the other fringe royalty and the gravy train will stop at the next station. Unless of course they can ween themselves back into the fold when Liz gives up the ghost.