It's going to be a very different 2017-19 if someone like Davis is in charge and also finds he can't get his Brexit plans through Commons - you can't say
David Davis isn't truly a brexiteer and if only a true believer was in charge. But then he also took the view (admittedly when he wasn't in Cabinet anymore) that
we should no-deal if it came to it, so he might decide "sod it we're doing that" and actually do it.
At which point I'd assume there'd be an attempted no-confidence vote like in 2019 but it'll run into the same problem that many MPs on the no-conf side don't want PM Corbyn and won't vote if they think they'll get him.