Seems to me Muhammad is a well documented historical figure. -Tom
Academic scholars such as Angelika Neuwirth, Christoph Luxenberg, Patricia Crone etc. examine early versions of the koranic texts and appear to agree that Arabic is not the mother language in these original texts, which makes sense given the Arabs were predominantly illiterate.
Scott's hypotheses are largely derived from surviving historical artifacts. Ask yourself, is it mere coincidence that throughout the existence of Islam, doctrinal jahiliyya triggered the elimination of artifacts and evidence contrary to islam's established narrative of supremacy?
The Hadiths were collected and written down centuries after Mohammad allegedly lived. I think the theory is plausible. In a very literate society where the Moslems were rulers, why is it that the Koran is not written until the 8th century? And no coins commemorating MOhammad or Islam until much later?