"We'd just leave, anyway, on WTO terms"?
That is a wholly untested hypothesis, and it does not ring true.
Far more probably, we'd just remain, anyway.
Although that would assume that the rest of the EU was prepared to keep us.
Again, that is a wholly untested hypothesis. Again, it does not ring true.
The best possibility would be that the competing Conservative and Labour versions of Brexit would be put to a General Election.
That would happen after the House of Commons had approved Theresa May's deal while the House of Lords had rejected it, no matter what was in it, because that House was irreconcilably opposed to any withdrawal from the EU.
But that is a best case scenario, and when did one of those ever come to pass?
And that is before we even begin to consider the likelihood or otherwise that Theresa May will be Prime Minister in two years' time.
There ought indeed to be a General Election between the competing Conservative and Labour versions of Brexit.