Has he been over in the US? Just about every week the Globe tabloid .has some plot Camilla has to pluck the crown from Elizabeth for herself.
Seriously though. It sounds true. Prince Charles is 68. I am fairly sure he would not want to suddenly have the burdens of the job on him. I am sure he has a routine that he probably does not want to change.
Prince William, age 35, I suspect does just as much good as Prince as he would have as king, he also would lose a lot of freedom. Giving the life spans of this family (his grandmother,grandfather and great grandmother) he may not be crowned prior to being 60. I do not know how long the Spensers live.
Prince Harry well he can forget it. The odds are remote.
Although would you take it? You would have the power of a flag, need to do ceremonial stuff and live in the swankiest prision around since your freedom of movement would be zilch.