It's simple: No one wants to work in the trades anymore.
It's hard work, you get completely wonky hours and you are expected to go at anytime.
You are always in the field and you may not get a break, plus long hours.
ALSO, in some areas (like where I am, Manitoba) no one can even get into the trades because no one will accept new apprentices - the wait list is literally a few years long. That instantly makes it not worth it, as you can go right back into school and get another degree or certification in that time in another area.
Why would anyone want to wait 'years' to get an apprentice, just to get wonky hours, long hours, and being expected to go at all hours of the day. It simply is 100% not worth it.