One really big math problem with that theory.
About 85% of the voters in the UK are white Europeans.
In the USA, about 66% of eligible voters are non-Hispanic whites.
In the USA, about 33% of eligible voters are non-white.
Non-white Americans vote 75%-80% for the Democrat Party.
What Trump proved is that the inevitable is not inevitable.
He proved that with his election. He proved that with the economic cycle of recession that has proven to not be inevitable.
That Democrats get the minority vote is not inevitable. Only Democrats think in terms of identity group votes.
True Republicans and Conservatives believe in individualism and the ability of each Black, Brown, Yellow, Green and Orange American to be reached and convinced of reality.