Jug- and Jarhead are both nicknames which have been used throughout history, although Jarhead is perhaps more common nowadays if you say so. For recalcitrant mules and stubborn Marines. But not a term of derision, more one of affection - for something/someone which digs in and won't be shifted!
It is not me who confuses the stereotypical USMC Hollywood image with reality; however, your posts may lead others to believe that the Republic movie company's portrait of your Corps is perhaps correct.
We had a USMC back-seater on the F4 training staff when I did the course. One day there was some formal inspection due and his colleagues asked him "Are you going to be turning up in that khaki outfit with all the medals and the Boy Scout hat - or that Glenn Miller $hit?" Brave words, but Ed took it in good humour! The 'Glenn Miller $hit' (Officer's Dress Uniform) won the day.
And the USMC folk who invited us to the embassy in Dakar were nothing like G/Sgt Thomas Highway or his movie clones, I'm glad to say!