That's just not true. I have some interest in types (mostly practical, some theoretical) but I have no graduate degree, I still regularly encounter both theory

That's just not true. I have some interest in types (mostly practical, some theoretical) but I have no graduate degree, I still regularly encounter both theory and type voodoo I don't understand, and I wouldn't consider myself a "type system expert". On a recent project I was able to use the type checker to help me catch things including 1) passing a bid price where I meant an ask price, 2) using an index into the wrong array, 3) calling a function not permitted to run on the thread in question (because of data access or deliberate marking). This wasn't Haskell - it was C.