Why wouldn't players be perfectly interchangeable widgets to the "traditional GM"? They don't want any contributions except character actions.
I would never have come up with this phrasing myself, but--yeah, this is precisely the problem I have. With all of the emphasis on "absolute power", on GM vision, on it being "my campaign" from that GM's perspective, the bottomless dismissiveness for the very concept of player contribution outside of character actions? As far as I can tell, to the "traditional GM", the players are perfectly interchangeable widgets.
They just happen to be the particular perfectly interchangeable widgets which coincidentally ended up experiencing that campaign.