The Fantastic Four are dissolved in the comics because nobody bought their comics so they decided to try something different.
For anyone who hasn't had the 'pleasure', the Future Foundation vol 2 and the run of Fantastic Four it tied in to were almost certainly the worst mainstream comics I've read in 40 years of comic reading. Truly, truly dire.
It's shame, because the preceeding stuff by Hickman wasn't bad and neither was the 'wrap up' story by Robinson.