What I’m getting at, of course, is that despite a gadol’s fallibility, he still has a better chance of being right than a non gadol, so why wouldn’t you avail yourself of that for important decisions?
Unless he is ignorant (or chooses to ignore) of the facts, or even worse, Nogaiyh B’Davar (Like many “Roshei Yeshiva” when asked if one should stay in Kollel). Remember the (rather famous) story with Rav Chaim and the basketball*? I would rather ask a doctor who knows medicine, a lawyer who knows law, etc. than a “Da’as Torah” who feels the need to respond but doesn’t know the facts, or even worse, makes them up. And when the Torah says “Shochad Ya’avor Einei Pikchim”, it means Da’as Torah as well.
* Yes, there is an opposite story regarding the Chazon Ish and brain surgery. If someone with Da’as Torah was able to prove they were qualified like the Chazon Ish was (in that story), then there is what to talk about.