Income does not corollate exactly to relations of production, but it is a decent enough independent variable.

CNN 2020 exit poll - income over or under $100,000. The majority above voted Trump, majority below voted Biden.

https://www.cnn.com/election/2020/exit-polls/president/natio...

With regards to liberals abandoning the working class - this did not happen because liberals were never for the working class. Nor were conservatives.