I'm looking up videos of Van Morrison, and that poor guy hasn't aged well. He hadn't aged well in the 90's either. He sounded like a mafia guy trying to do beatnik style poetry on "Moondance".
It's jarring to hear, after listening to it from the recordings in the 70's. I know his voice won't be the same, but dang.
Jackson Browne (even though he's a massive hippy) still manages to pull off a decent rendition of his hits. Or at least, he did the last time I saw him, which was a while ago, so as of right now today your mileage may vary. "Running on Empty" still sounds like the same song, not a spoken-word homage.