First, it depends on how you define poor results. I’m sure you’ll say everything Monte touches turns to dog doo, but prior year win/loss record does not necessarily mean poor result. Otherwise, Sam Presti should be shown the door for their poor performance over the past two years. It obviously needs to be more nuanced than wins and losses (I grant you not forever). So if you take record aside as the measure of poor performance for a GM, most everything else Monte has done can be argued one way or the other qualitatively in the context of his longer term vision.
Second, I would argue being an nba GM is unlike 99% of the jobs in America. You may say that just shouldn’t be and they should be held to the same standard as the rest of us hard working Americans, but that’s just not reality. They sign multi year guaranteed contracts, but can generally be terminated at will by their employer. They are hired, extended and fired for a variety of reasons, some of which is for PR purposes. They are a decision maker, long term team architect/planner, manager, public relations front man, owner scapegoat. They are very often extended for the sole purpose of projecting stability of leadership, and fired to “shake things up”, often disconnected from any quantifiable short term performance. This is all just not very common in any “real world” job. The closest you probably get is the figurehead CEO, and I would argue that world is even more absurd with golden parachute payouts for a terminated CEO that has driven financial performance into the tank.