The majority of programming jobs, DevOps jobs, etc. could be learned in a trade school. Only a minority of programming jobs really require a four year CS degre

The majority of programming jobs, DevOps jobs, etc. could be learned in a trade school. Only a minority of programming jobs really require a four year CS degree. Also, is that true that most trades can be learned on the job without prior training? I thought you needed a decent amount of training to be a plumber, electrician, etc.