A British friend told me that the Queen will decide who gets the crown - Charles or William. It's her crown so she decides who gets it. She told me this about 15 years ago and she told me that most people in the UK at that time wanted Wills to get the crown and not Charles. At that time, she told me that Charles' nickname with the British people was Jug-Ears and Camille's nickname was "the Rottweiler".
Prince Phillip could not be named King because he was not born in Britain - he is actually from Greece. Several years ago I heard the story on why a foreign-born sovereign could never have the title King or Queen. Several hundred years ago, someone from the Continent married the Queen and became King. After the Queen died, the King wanted to move back to the Continent and take the crown with him. To prevent this from happening again, Parliament passed a law forbidden the foreign-born to ever have the title King or Queen.