I called it the Velvet Trap when I was a window cleaner. Yes, there is nothing wrong with earning a living by manual labour and having a trade skill is as valuable to society, or more valuable, than most white collar careers,
BUT.
There is no skill progression and no career progression in window cleaning. The only advancement you can make is to take on more work.
Compare that to something like carpentry. Your skills and abilities increase over years until you can call yourself a master craftsman. You can go from doing utilitarian work to practically artistry.
The reason that window cleaning is a trap is that to earn a decent wage takes all your time and energy. How can you take an evening course to learn a different skill when you come home physically exhausted every evening? The Velvet part of the trap is that you can earn enough money to earn a decent wage, so you would lose money if you stopped window cleaning and started in a new trade.
The only reason that I escaped is because I fell off my ladder while window cleaning and the government paid for me to retrain as I could no longer do my job. I thank Dog every day for that slippy bit of patio!