Do the math: The number of professorial positions is not growing (or not very quickly). Under steady-state, each professor only needs to train one single tenure-track PhD in their entire career. (Or maybe 10 professors need to train 11-12 students, to account for various forms of attrition.)

If you want more PhD's than that, you have to figure out a place for them to work; industry is a good "pressure relief valve".

That sounds like an excellent thing based on that last sentence. Anecdotally, I hear people talk about trade school as being much more practical compared to the majority of traditional 4 year degrees. So I am interpreting a "move towards trade school" as an increase in practicality and therefore utility to the student.

"Learn what we believe to be the textbook-correct, fundamental, foundational theories for a topic; learn about the frontiers of new research in the topic; find a niche on that frontier where there's something new to try; try something new; write down the results (no matter how boring); share with your friends; rinse, lather, and repeat" is a perfectly respectable trade.

No reason why the good plumbers, electricians, or truck drivers of the world ought to look down on academics-- no matter how stuffy or highfalutin or soft-handed they might seem.

Every once in a while, academics come up with something useful. (And in fact, I think that that might just be the whole point).

There is a non-insignificant segment of the population that would have been better suited and employed as painters or HVAC technicians than for their chosen careers. Some software developers (and 80% of the city of Portland) would also fall into this category. The world has a surplus of PhDs opening cupcake shops.

Germans are big on trade schools. Despite being one of the richest western european countries, Germany (and Switzerland) have along the lowest college graduation rates, because they prioritize trade schools.