Like they used to say about Joe Montana, he threw soft because he couldn't throw hard. He was successful because he didn't try to do what he couldn't. I couldn't rock out harder than everybody, or overpower people with mastery like Jack White of the White Stripes, so why try? That's why I've always worked harder on words.
If critics were harder on the musicians that they love, there would be better songs. But as they grow older and they lose their talent, critics refuse to let them know that and protect them, and they get to the point where they put out music that just isn't up to the levels where they've already been.