> Why do people in "tech" outsource their judgement on this topic to people who aren't even in the room, a mythical "average person", every single time the issue comes up?

The same reason they use the "average person" as a straw man in arguments about OS usability and whatnot: deep down they believe that they are better than other people because they know tech stuff. People can sense this too, it's one of the reasons tech people, as a group, aren't well liked.