Computer and technology are drastically changing white-collar jobs, but they have not yet had an impact on blue-collar jobs to any great degree

This answer is a true or false answer so its true

What about fast-food and retail/grocery cashiers? What about library pages (book shelvers)? What about secretaries?

I think the statement cannot be answered is such a binary fashion.

What about all those miners, car, and steelmakers they don't need because of technology?