Citation needed? The UK certainly has plenty of upper-middle class families. This is nothing to do with family wealth and everything to do with business culture.
The UK is a class society much closer in nature to East Asia than the United States. Wealth accumulation is still to a great extent occurs along the stratified classes and they ain't sending their kids to engineering schools.
Again, citation needed. These are extremely broad claims about the nature of British society. Or just go ahead and downvote me if that makes you feel better
