Quite - it would be a betrayal of both William and Catherine, and I can't see Charles doing that however much he's a silly old sentimental, guilt-ridden father.
I think what we ask of the monarch and their family in the 21st century, with all the loss of deference and the protection that gave, and the vile social media and press intrusion, is huge. I'm a constitutional monarchist and my only concerns about the continuation of the institution aren't based on resenting the so-called privilege and perceived out-modedness of it, but rather the massive ask that someone dedicate their life (until death) to the role, living an exemplary public life and performing high-level tasks which must be got right.
I couldn't do it. I get that some people are republicans, and I respect sensible, well-informed republicans, but the sort who think it's an easy gig, with loadsamoney and just parties all the time...not so much.
Therefore I think for a modern man like William, who's been to a relatively normal school (not home-tutored) and seen how the comfortable middle-class lives (the Middletons), and who has been through the last few traumatic years, I think he could be easily pushed over the edge if KC made concessions to Harry. It's like the story of the Prodigal Son all over again! Why would he bother?