What acts have had a huge selling album and the follow up sells far less yet is critically favoured by fans and music critics? (Every Huge Artist Has A Tusk)

Smiley Smile, maybe? Although I guess you have to be pretty contrarian to prefer it to Pet Sounds. If Smile had come out when it was supposed to, it would be the ultimate example.

couldn't you make the argument for Pet Sounds itself? I was under the impression that it didn't actually sell very well at the time

Ha, yes — was just about to post that caveat

pet sounds was not "huge selling" at the time.

It met with a lukewarm critical and commercial response in the United States, peaking at number 10 in the Billboard 200, a significantly lower placement than the band's preceding albums.

xps

kinks following up lola, which at the time was their big comeback album, with muswell hillbillies probably fits here.

A measly 9.2, Rumours the p4k gave http://pitchfork.com/reviews/albums/21924-tusk/

p4k *fave that is

one of the better written reviews I've read lately imo