Yes they are a route to financial independence, but there's a hidden cost that a banker, marketer, SEO expert, programmer, manager, etc. does not have to pay.
In mental labor you get fat and achy sitting at a desk all day, your sleep schedule gets messed up looking at artificial light constantly, your mental health degrades and your risk of suicide increases - obviously it's also unpleasant.
We can all agree the manual laborer's job is hard because no one can really escape manual labor. Even if your profession doesn't require you to lift a finger, other things in life like taking care of a home expose us to plenty of comparable tasks, and we can easily imagine how much worse it would be to do these tasks all the time. But the manual laborer can forego most of the negatives of office work which require prolonged and continuous exposure to things we would never experience in nature. Thus the manual laborer tends to see greener grass on the other side while the office worker does not.
Any office worker can do exercise to mitigate their risks, no labourer can magically make his bad back or destroyed knees better again.
The trades are excellent careers. The issue is see with those careers is that people in the trades don't look ahead. No one wants to haul roofing shingles at 45 or crawling under houses at 50. A master of their trade commands a high hourly rate and should be looking at teaching opportunities, running their own shop opportunities, safety opportunities, or general project overview.
It’s because they’ve been sold a lie that a degree is a free pass to the middle class. If you thought all your kid had to do for a middle class lifestyle was study differential literary analysis, you’d be onboard too.
This is the false dichotomy that’s causing students to incorrectly go to college when it might not be the best path. There is a massive gulf of the middle class you just glossed over between college and Walmart/meth: the trades. Working in skilled blue collar fields (electrician, contractor, plumber, diesel mechanic, etc) will likely give you a better life financially than someone who graduates with a 4 year BA.