The decline was when they brought in Ron Wood, he’s not half the musician that Mick Taylor was, but Taylor’s personality didn’t quite fit the band.
They did lose personal over the years. I think what strikes people most is that the creative decline of the band was so fast & early. One would expect a slow decline considering the talent they had.
Pure props to Mick Taylor but Ron Wood has few peers as well. Beast of Burden is some fine playing. IMHO