Some degrees are not worth paying for, I'll give them that, but as you've stated there are many careers that nobody would (or should!) trust you to do without some type of evidence that you are qualified to do them.

I went back to school at 32 to get a BS in Accounting. My earning potential before that was about $15/hr. Afterward it's unlimited. Because college taught me much more than just accounting. It taught me how to think, plan, strategize, etc. And of course, it taught me the language of business.