The median salaries for skilled trades aren’t great. You can make good money if you are willing to work a ton of overtime, or if you can manage to get one of the very limited union spots in the right city. Or if you become a business owner (and accept the corresponding risk) and mostly manage other skilled employees.
It’s also not a viable solution for more than a small percent of the population. Let’s say AI comes along and forces 25% of the white collar workers out of a job, there is only enough room in the skilled trades to handle a tiny fraction of those displaced workers.
That’s ignoring what massive unemployment does to salaries in the trades. And the fact that to make decent money in the trades you need years of working for peanuts first. And if you think age discrimination is a problem in tech, try breaking into the trades as a gray beard. The entry level jobs are built on the assumption that you are 20 years old and can do 12 hours of hard physical labor without needing a week off to recover.
Again it’s not impossible, it’s just not a solution at any kind of scale.