UK General Election 2017

[Pannonian]

Your missing the point. I put "majority" in inverted commas for a reason. It doesn't matter that a 40% win is less than the 48% lose of Remain:
You only win in fptp by extending your appeal beyond the faithful.
Remain lost.
Parties that seek to win (Labour, despite Corbyn, and the Tories), can only achieve what they seek to achieve by taking majoritarian posiions even when it is outside their own sectarian interest. Blair is a classic example in wooing the middle class.
Thatcher is another in pulling in the southern working class.

The body is willing, but the mind is not. This is the Labour/Corbyn problem in a nutshell.
Even when Corbyn accepts the 52/48 result, it is because it fits with his worldview.
But he continues to talk about Palestine, and (virtual) pacifism, when these positions are thoroughly irrelevant to a useful 'majority' of the electorate.

Er, that's my point. When a main party gets 40% in an election, that's 40% voting for them, plus an implied 20% who didn't vote for them but who aren't especially opposed to them (the other part of the centre). Corbyn has solidified his core, but anyone outside his core aren't just not voting for him, but are actively opposed to him. There is zero attempt to conciliate with the voters outside his core, such as is necessary for any electoral victory, but instead he actively seeks to turn Labour into an irrelevance (the Labour party does not exist to gain power, but to be a movement, etc.) When the other main party sidelines itself into irrelevance, it renders the centre moot, as there is no longer a constituency vote that didn't vote your way, but doesn't really oppose you. That leaves the ruling party as the only party capable of gaining power. In most cases in the past, the ruling party is moderate enough to bear the other voters in mind whilst in government. But May sees no practical reason to, and neither do the Brexit side. Victor gains all.

In US terms, imagine if a single party has just enough power to pass constitutional amendments, due to the other party being utterly inept. Then, when they gain power, they rip up the constitution to solidify their hold on power.