I appreciate the statistical approach, but it presupposes that every club has had the option of playing a really, really good teenage centre back, which isn't the case. Arguably, the only clubs that had the chance to do so over the last 5 seasons were Arsenal and Everton, and neither Saliba nor Branthwaite were nearly as good as Yoro as teenagers.
I'll certainly accept it would be a gamble, maybe even a little bit silly, but once again, that's why we're all in agreement that just the one defender wouldn't be enough.
I largely agree with the rest of your post, but I don't think it's a crazy thing to prefer Yoro over De Ligt in the (hopefully unlikely) event that we only sign one defender. Short term pain for long term gain and all that.
As an aside, an argument could be made that Yoro and De Ligt is an either/or and we're still targeting another centre half. Both players prefer to anchor the defence and do most of their work in the width of the six-yard box. Aside from the obvious of being left-footed, where Branthwaite differs is that he's happy to do a lot of defending in his channel, so we might turn our attention to a defender more closely aligned to that skillset, along with Yoro/De Ligt.
I'm not entirely convinced by that argument myself, but it might be worth thinking about. It's probably more likely that Ornstein's "expectation" that it's an either/or changes according to who we can sell.