Bannon figured that he could be successful manipulating the GOP nominations process and that the Mercers would continue to back him. So he felt he could set himself up as an internal GOP rival to Trump and diss him whenever he felt like it.
It didn't play out. He was unsuccessful in all the 2017 special elections. He fucked up spectacularly re Roy Moore and lost the GOP a crucial Senate seat. The Mercers dumped him. So he desperately tries now to suck up to Trump and get Trump to like him again, like a sad bitch.
It all makes Trump seem like a 'sane genius'.
I bet this whole 'Fire and Fury-gate' was just a small example of Trump's maniacal genius on display.
1) Invite Michael Wolf into the WH.
2) Treat Wolf as part of the 'family' to gain Trump's trust and convince Wolf to write a book about the WH.
3) Have more than half of his WH 'family' feed Wolf juicy morsels of gossip which would make Bannon extremely jealous.
4) An unrequited Bannon then goes all vindictive and feeds Wolf with 'baseless garbage'
5) When Trump is satisfied that Wolf has enough juicy 'garbage' to print he orders Wolf to seek a publisher.
6) Book and gossip out in the public now, Bannon exposed as mentally unstable and a Dotard compared to Trump.
7) Trump wins yet again due to his ginormous sanity and world conquering genius.
The lesson from all of this?
Don't fuck with Trump's insanity and stupidity.