UK's Conservative party is one of two main parties and arguably dominant in the UK.

But I don't understand how did they manage to pull that off in the century XX with its urbanization. As one would expect, the working class is going to vote for the left. The "intelligentsia" also leans left and the urban middle class is going to be divided between two.
Theoretically, that's game over for conservatives: their primary voters are rural folk who are shrinking, and the capital owners, who no doubt prefer Conservative policies, aren't numerous to begin with. Recent immigrants are also expected to vote for the left.

This hypothetical picture actually seems to come true in some elections.

Even in the USA, Republicans seem to have some electability issues lately. But overall, US seems to have much more domestic capital, and farmers which actually contribute to the economy, and the Dem-Rep distribution looks more territorial. So I would expected the UK's conservatives to lose competitiveness faster, and UK to behave like one large US coast for political purposes. But apparently it isn't so. Why? What do Conservatives do right?