It's an old American idea, much adored, that anyone can do anything- a plumber can be President.
BUT a plumber can't be the President. A plumber might become the President.
So through hard work anyone can do anything, but lots of people seem to forget the part about going thru the process which may be very difficult and time consuming in order to arrive.

Not many movie stars and rock stars become politicians- and those that do, are no better than any plumber becoming one. And because it might be somewhat easier, probably on average worse than any plumber who becomes a politician.

John Lennon was a talented musical performer. And it was wise of him to look for all kinds of inspiration. So he was a great entertainer- maybe one of the greatest.
Too bad there was so many shallow idiots who thought of him as something other than a entertainer. And worse, imagined he was some kind of god.