What if Leonardo da Vinci had never been born?

Leonardo da Vinci has always rather puzzled me, as an historical character. Certainly, a great artist, but, also celebrated as a great scientist and engineer. Although, his actual success and influence as a scientist and engineer appears to have been virtually nil. Certainly, he did attempt to sell his services and popularize himself as not merely an artist, but as an all purpose intellectual who could solve any and all problems a potential patron might face. And, this technique worked astonishingly well, spawning numerous imitators, both then, and now. Was Leonardo really as great a genius as he presented himself to be, or, was he merely a highly skilled hustler with considerable artistic ability? I'm not really sure, what do you think? How does history change, if at all, without Leonardo da Vinci? And, if his actual influence on history was minimal, how could he truly have been a "great genius"? Or, just possibly, was his great genius simply his skill at marketing himself? Bear in mind, Leonardo was certainly a homosexual pedophile. And, even at the time, this behavior was a Capital offense. So, is it possible Leonardo's "genius" consisted mainly in his deviousness, and this applied not merely to his ability to avoid being executed for his crimes, but also to his ability to market himself? Could it be that Leonardo's criminal tendencies and skills generalized from avoiding criminal punishment, to obtaining the devotion and interest of society as a whole, including the most powerful men of his time?