I think the people in this discussion are using the word "monk" in different ways. A monastic martial artist (monk) may not be a strong enough trope to merit a character class, but an adventurer who fights effectively without weapons and has semi-magical abilities gained through exemplary training and some version of "inner strength" is a trope that has stood the test of time. The 5e monk class is reasonably close to the latter.
i think most of the current monk stuff would/should go into a ninja type class, running up walls, some elemental abilities, evasion and mobility based defences, disabling strikes, an emphasis on skill over raw power, but i think you could get some good mileage out of merging some monk concepts with the barbarian, some kinda fist fighting boxer, unarmed and unarmoured, take out the evasion aspect of the monk and make them tanky and enduring.
I disagree strongly. The ninja has sole grasp of some abilities, but few if any of them are in the base monk class. Running up walls and moving lightning fast and the like are just “Unarmored master”, not specifically ninja.
And you’d be right. The other poster is exaggerating the importance of who first asked for the archetype to be a class, and how tightly the inspiration was drawn vs drawing from the same inspirations as the cited source. And that’s just the first iteration. Every iteration since has been influenced by broader Wuxia and kung fu inspirations.
This jumped out at me. I'm not quibbling with any of your other points... but to me, D&D monks firmly have their roots in Stephen Donaldson's Haruchai/Bloodguard, not cheesy Hong Kong action movies of the 70s.