Agree with certain amount of what you say, Richard. But can't quite follow

"And what about Dylan's making new songs out of existing ones (both traditional ones and recent ones such as The Patriot Game)?"

Where did Dylan do that? If you mean writing new words to the same tune, that is not "making a new song out of an existing one", it is simply reusing a tune. (And, tune-wise, 'The Patriot Game' is not recent; its tune is a version of 'The Grenadier & The Lady', aka 'To Hear The Nightingale Sing', as I once actually got Dominic Behan, who till then had sort of let it be generally understood that he had composed it himself, to agree during a correspondence in Folk Review.) If that isn't what you mean, show, please, where Dylan performed the action you urge, of "making new songs out of existing ones".

≈M≈