You may learn more in certain areas than others by learning on the job, but after a certain career level, you will find that employers in many culinary careers require a culinary AOS degree and/or a 4 year BS, regardless of how many years of work experience you have. It all depends on what you what to do with food and you career and how far/fast you want to advance.
I worked in restaurants for 8 years before I went to the CIA. All I can say is, I didn’t know what I didn’t know. Gastronomy, The science behind cooking, restaurant law, wines and Menu's, culinary math, ethnic cuisines from around the world etc... I knew nothing about any of this before I got to school. But now I use most of it almost everyday in some for or another as a corporate research chef.