One thing I think people have not caught onto yet is that the Conservatives are going to get squeezed in their heartlands for a key reason:
The housing crisis.
Because it is now too expensive to live in the cities, young people, minorities, and families are moving out into smaller cities and towns where the Conservatives have held for a while, but not with a fairly strong majority.
While they will leave Labour areas, the large cities have enough excess votes for Labour that it is of no problem.
So, the Conservative failure to do anything about the housing crisis has unintentionally forced a wholesale demographic shift in their usual geographic base.
You reap and you sow.