I don't think TPTB want Charles or any of his descendants to be heirs. Whether specifically for the reasons mentioned in my OP or not, I doubt he will ever want to be allowed to ascend the throne. I think it would be easier for TPTB to manipulate and control someone as naive as Princess Anne.

I suspect Will, Kate and the new baby may have a tragic fatal "accident" soon, just as Diana did. Nothing like giving the nation and the world false hope (look at all the attention the world are giving them now) and then ripping it from them. Can you imagine how traumatised the world would be? A perfect time for TPTB to manipulate the masses, just as they did after the deliberate cold and calculated assassination of JFK.