The pay is quite good right now. A skilled welder willing to move around can clear $100K per year and it can go above that, especially if you run your own business.
Lots of folks don't consider the trades "prestigious" enough.
Obviously it's not good enough. Bump up the pay to $500k, and it will magically become "prestigious" enough. I also wouldn't want to wreck my body for $100k if I can make $80k sitting in an office at a keyboard doing a Mon-Fri 8AM to 5PM and get to sleep at home every night. And work from home during a pandemic.
Right now, society is taking advantage of people who have to sacrifice their bodies because they have no other options. If the supply of people having to sacrifice their bodies drops, then the price point has to rise to compensate for that.
Well, the people not going into the trades don't have an $80k office job option. They're alternative is a $30k retail job and they still don't want to go into the trades.