ADD - "Many of his popular contemporaries (Jimmy Stewart, Ted Williams, etc.), as well as, the general population - in his circumstance -, jumped through some small hoops to enlist and serve. ..."
Neither Jimmy Stewart nor Ted Williams had to jump through any "small hoops" nor did they "enlist."
James Stewart was already a pilot in the USA A.F. Reserve, and Ted Williams was already a trained fighter pilot in the USMC Reserve. Both already had highly useful military skills. They were going to war no matter their celebrity status.
In 1941/'42, John Wayne at 35 years of age, had
no military skills whatsoever, unless one were to count his having used a Winchester rifle in
Stagecoach.
Wayne did have a bum knee from playing football at USC. How much that would have affected his being in the military I do not know, had he been a military member.
I strongly suspect that the Army or whichever branch of service, would never have placed Wayne in a combat unit.
More than likely he'd have been making training films and traveling out to the American cities and towns to sell war bonds.
One could counter that by saying, "Well Clark Gable joined the USA AF when he was 42 years old, so there!" Uh huh, but Gable was absolutely devastated by the death of his wife, the actress Carol Lombard, who was killed in a small plane crash when she was on a U.S. War Bonds selling trip. Gable never got over his grief about her death and from what I've heard really didn't care much at that time if he were killed fighting.
Gable, however, after Basic Training was appointed an officer and assigned to training machine gunners who flew on our bombers to be accurate firing at moving targets. Gable was well known as a fantastic shot hunting ducks, geese, quail, etc. Gable did fly as an
unassigned side gunner on a bomber for several combat missions, unknown to his superiors "upstairs." It was stated later he made a partial kill on a German fighter.
Many years ago in L.A., I knew a man who was
NOT in show business but he'd been Gable's good friend and hunting partner. He told me that Gable was taken off flight status and his superiors said "Captain Gable, we have no shortage of side gunners on our bombers, but there is only one 'Clark Gable.' You're going home to sell War Bonds." Which he did.
Long odds are if John Wayne had been in the military, he'd have been selling War Bonds too.
Just my take on it.
L.W.