I used to work as a diesel mechanic.
Trades are great, but we, as a society, are not really prepared to deal with them. It's easy for someone working a comfortable desk job to say "those kids should go into the trades" without realizing the following things:
1. Trade jobs often involve non trivial amounts of physical risk.
2. Trade jobs rarely allow you to work until normal retirement age (65 or even 70). I never met a diesel mechanic over the age of 50, and precious few in their 40s.
3. Despite all that, they don't pay as much as your desk job.
If you're going to sit a kid down and give them the option between a physically demanding, difficult trade job or a climate controlled, higher paying desk job, what do you think they are going to choose, realistic or not?