The style of music changed as the years went by, too. But to me the voices stayed the same. I think I like the younger/earlier voices.
Glenn sounds so much better with his true voice, which is, to me, that nasally Midwest, Detroit accent. My late ex-husband, who was from Iowa, had the same accent, was a musician and sounded just like Glenn. Especially on 'Take it Easy".
Later, they were all getting that old-person warble in their voices. Don Henley has it the least..