[Eddie01]

Prince regent can not wear the King’s Crown. Ever. Which is nice.

His mare can’t be queen either.

[PAR35]

Prince regent can not wear the King’s Crown. Ever.

Where are you getting that? It's certainly not the historical outcome.

[jjotto]

The king who became George IV was Prince Regent for George III.

[Verginius Rufus]

King George IV was king from 1820 to 1830. He had been Prince Regent the last 9 years of his father's reign after George III became hopelessly insane. So Charles becoming Prince Regent would not preclude him from later being the monarch.

The longer Elizabeth II lasts, the better for him--if he is in his 80s when his mother dies, the public might be willing to endure him figuring that he won't last very long. He's 68 now, will be 69 in a couple of months.