Well, I don’t think those two are comparable. Clapton inspired Eddie Van Halen, but EVH sounds absolutely nothing like Clapton. Yngwie sounds a lot like Uli Jon Roth. But certainly I don’t actually disagree with that. He did take it considerably further of course, I’m just saying I myself was pretty surprised at how good Uli really sounded for 1976.
Not to mention my point is less about their exact technical abilities, it’s more about the entire sound and style. The harmonic minor scales, the phrygian dominant, the arpeggios, the dark, classical influence. Now if you wanted to take Blackmore and say that Yngwie quadrupled him, that I would definitely agree with. But just to be clear I’m not really in disagreement with you. Yes Yngwie took Uli’s style considerably further, but if you go back and listen to Uli, he was incredibly technically-advanced for his time, also considering the gear that he was using.