The thing is, if you are in the RF as a 'senior' member, you get asked to undertake public duties. You don't have to try to generate them, and you can say you would prefer to have a more private life, but y'know, Duty and Service.
If you leave it, you don't automatically get asked. So you have to either a) fade into private life or b) admit that actually you do want a high public profile.
KC, W&K etc don't have to go looking for for opportunities to be in the public eye, or seem relevant. Because they have a constitutional role (whatever you think of having a monarch as head of state, that's what we have at the moment, personally I think it is a bit ridiculous).
So they don't have to justify their public appearances.
H&M, however, could disappear into private life. Every public appearance is because they have chosen to make that appearance to please themselves. So it highlights the fact that they are choosing the public profile, while complaining about having a public profile.
That's why they can't square the circle.