The many people who would have done manual jobs in the past are no longer really needed, except for minimum wage jobs.

I'm not certain that I understand your point, but it doesn't seem entirely right.

I look at the numerous manual jobs that are done now by people around me: (1) people who mow lawns and trim trees--these are certainly needed and are not necessarily minimum wage; (2) people who use the large machines are certainly in a sense doing manual labor; (3) plumbers work with their arms and hands--and given their wages, are both needed and definitely not minimum wage; (4) animal control officers and police, who often must run and chase offenders; (5) construction people certainly do manual labor, and not for minimum wage and are definitely needed--try paving roads sometime; (6) there are many, many people who work in the office by day, then labor in their gardens or tool sheds by night, doing manual labor for pleasure.

There are numerous manual work jobs that are both needed and high-wage--and many people actively delight in manual labor.

It is somewhat true that we regard brute force manual laborers as somehow "lower" than skilled workers, who are also often paid more. But there are numerous jobs that require both manual work and skills (try climbing up 100 or more steps to maintain a 3 MW wind turbine).