We are still waiting for Rumours 2
It seems the band was always chasing commercial success after Tusk which was exactly what Tusk was not. Tusk changed the band forever. Tusk was very creative and has lots of great songs and one of their best albums. However sometimes I wonder what kind of creative albums we could have gotten if the band was not so concerned chasing pop radio. Mirage and Tango (the next 2 Mac albums) were the most commercial and super pop corporate music. In that regard, was Tusk really worth it? IMHO, the band never recovered always trying to over compensate for Tusk. IMHO Tusk had unintended consequences and not for the better. After Rumours, the band lost their "rock chops" which is why on classic rock radio stations today you will only hear songs from The White album and Rumours.
(now THIS is a heavy thesis)