When I was a young pup in the 70's, I remember eating at JITB's in California when visiting my mom's sister and her family. I didn't really like it, as I was so used to Burger King (hq'd in MIA where I was growing up) and McDonald's.

My aunt said the name stuck as it was somewhere you can get food of any type, but it was not very good as they seemed to be a "jack of all trades, but a master of none."

I guess with the menu variety shown in the quoted post, I can see why.