> degree holders used to be a minority in white collar work.

That's still nearly true, if not true. 60% of jobs are white collar. 40% of the workforce has a degree. Data quality starts to decline somewhat here, but it is expected that 20% of degree holders work in trades or manual labour jobs. So, degree holders only just barely make up a majority on that basis. And maybe not even that as blue collar is usually considered to be more than just trades and manual labour, not to mention that we haven't even delved into other collars (e.g. pink collar) that further take from the degree holding population.