Maybe Lindsey saw this review and that's when he decided Tusk would be a bit more left field.
I've always wondered about all the talk of Tusk being a way to make sure they weren't painted into a corner by following a formula but if it wasn't for the success Rumours enjoyed then it would be little more than (as the reviewer states) the safe follow up to the very successful White Album. I bet at the time of the White Album selling four million copies they were probably thinking "Wow, there's no way we're ever going to top that number of albums sold!" so why not go for the unformulaic approach for their second record together? Maybe that wasn't where their heads were at the time but I guess it doesn't matter because Rumours is well worth having and without that we wouldn't have got the glory of Tusk as it is.