He still left his unmistakable mark. But in fact the decay was already making itself felt with W&W... One example: the unbearably sugary 'One for the Vine' or 'Your Own Special Way' (er... that's two, innit). ATTWT has its moments, but after that there were... no more 'rock' guitars.
And that period in time saw the end of the prog rock era as a whole, definitely.
I agree re: You’re Own Special Way. It’s completely forgettable. I disagree completely about One for the Vine. I think it’s a beautiful song. We can agree to disagree on that one.