Hearing people who 'aren't as good as they used to be' makes it all the more sad when someone like Lou Reed dies, who was still knocking out great CD's to the end (I even liked the 'Lulu' CD, although I'm in a small minority there).

Tom Waits is another, better now than 30/40 years ago (certainly more cutting edge).

As for changing your style to suit your changing voice, just listen to Joni Mitchell these days.