Nitpick: If there was a actual historical character who was anything like "King Arthur" he lived a long time (probably about 600 years) before the first accounts of him written in the Middle Ages.
Also, if Arthur really had been the Joel Spolsky of ancient Britain his knights would never have sat at a big round table, except during lunch. Rather, they would have each had an individual round table in a glass-walled soundproof office with a door that could close.
Nitpick: Nitpicking the historical accuracy of a reference to a '50s musical is a little nitpickier than average. (Next you're going to tell me the Jellicle Cats aren't really coming out tonight…!)
A good nitpick. I'm definitely on the 'Arthur as fiction' side of the debate. The first proper account of 'King Arthur' was from Geoffrey of Monmouth in the first half of the twelfth century; historical details place that Arthur in the late sixth century.
Ignoring the accuracy of a tale told more than five hundred years after the event, if Arthur was real and such an important figure, why did the Venerable Bede fail to mention Arthur at all during his remarkable (for the 'dark ages') history of Britain in the ninth century? /nitpick
Bede's was not a history of a homogeneous socio-political people, and Arthur, if he was any kind of early mediaeval king, was certainly not King of all Britain. The island was politically fragmented. Record keeping was poor. The very exceptionality of Bede's history would be one reason for its incompleteness. And wikipedia, at the time, was notoriously unreliable.
True, but Bede's history was wide-ranging and made no mention of Arthur or any other elements of his legend.
To the extent that Arthur could have been real, he likely would have been a warrior-leader, rather than a king, fighting against the spreading Anglo-Saxon invaders.