Since when is that the definition? Doctors and lawyers have never been considered part of the "working class." Software engineers, and other categories of jobs that didn't really exist in the 1930s, are more similar to those professionals than to working class people.
> People love to erode class solidarity by claiming that only people whose incomes are below a certain level are working class
You've got it exactly backward. The top 10% has been pulling away from the median American for decades now. They're beneficiaries of the same forces that have produced outsized growth for the top 0.1%. They write the software, paper the deals, put together the PowerPoint presentations, etc., that enable those trends.
The delusion among skilled professionals that they are part of the "working class," and their influx into the putatively labor-aligned political party, has had a tremendously negative effect on working class interests. They champion policies like globalization and mass immigration that benefit them at the expense of factory and farm workers. They spent divert vast amounts of political capital to social issues important to highly educated people, at the expense of economic issues important to the working class. And they make it impossible to pay for expansive social services the way other developed countries pay for them: by heavily taxing the upper middle class.
[0] https://en.wikipedia.org/wiki/Working_class#Marxist_definiti...
Challenge Accepted and won.
Not the person you're responding to but I wouldn't call a T61p brand new, it was released in 2012 after all.