I make good money and he throws me hundred dollar bonuses almost every paycheck, so he wants me to stick around.
He knows I'm capable, intellectually. I've created entire strings of formula that completely changed how his business analyzes financial data. They scheduled appointments on a fucking piece of paper that got passed around the office before I came along and said, hey, dude, calendar on the computer. I single handedly transported his entire book of business from one brokerage firm to another, because my manager is basically computer illiterate.
My best guess is frankly that I'm a pet for the manager to feel important so she'll stop asking for more responsibility/ education. She's been very devoted to him for a long time. She was a trophy wife before this job. Or, it's just overall shitty and archaic management from the both of them and my efficiency makes them look bad. Similar to your theory.