I honestly can't see why any Tory MP could believe that Johnson will suddenly be a vote winner again in two years time. I can see no conceivable way in which the GBP would turn around and say "well I know, wallpaper, parties, infidelity, Owen Paterson, Berlosconi, Russian donors, non-stop lying, [insert whatever else shit has emerged in the next two years because it's genuinely inevitable that stuff will]. But he's a laugh innit!"
I'm not saying that the Tories are doomed, I just can't see how Johnson would bring a net improvement in votes over a balloon on a stick with a face painted on it - or Jeremy Hunt/Ben Wallace/Liz Truss.
Alternatively, if you're of a conspiratorial mindset, the current state of play would be ideal for a Conservative party playing the long game. If you held a snap general election tomorrow then the best guess is that Labour Party would be forced to grant a referendum on Scottish independence in order to form a government. Given the unpopularity of all English politicians then it might very well pass - granting the Tory party power over England and Wales until the end of time without having actually got their hands dirty by being seen to facilitate Scexit.