Apologies for adding my thoughts to this thread - there are loads of other threads about H&M, but I reckon this one is probably the most sanest and knowledgeable.
Harry has been trying to strike out and make a life for himself, and probably would have done so if he'd been allowed to continue in the army. Meghan is different, and if the RF had taken that on board it could well have meant a move towards a more low-scale version of monarchy as happens elsewhere.
HM is elderly now, and I'm not sure she still has a firm grasp on how to deal with family matters. Even if she is still mentally alert, she's always done things the way they've always been done. Many aspects of the RF still harken back to Victoria's time.
This is a disastrous situation for the RF, but in my opinion it's of their own making. As Jephson's book points out, there isn't (and hasn't been for a long time) any kind of cohesion between the various royal offices. Communication has been the weakest point and it's really showing now.
I don't blame Meghan for going back to Canada, if that's true. She has been horribly vilified in the gutter press.
Just about the only thing the RF has going for them is the British love of nostalgia. And Kate, who has played her part almost to perfection.