It doesn't have to be a guarantee of a Corbyn government to scare me, even a small chance is too much. And despite your scenario, I still can't see a GE anytime soon.
And no matter how strong the Tory leader, I think the MPs will be terrified of No Deal blowing up the economy - even in the short term - and them being held accountable. Unless of course there was a referendum that made it clear that this was the desire of the people.
That is not the case now and only a referendum could clear it up outside of a GE.