Community colleges, which are generally not as expensive or time consuming, exist to provide exactly that to those who want that job-specific training. For everyone else, they can walk into the job without any training. It is not necessary. The best part of the American system is that you are free to do almost anything (there are a few exceptions).

I'm not sure there is any reason to spend four years and rack up huge debt for career purposes. College is for academic pursuits, not career ones.