I have noticed completely terrible casino attendance where I have been. This can happen from time to time ans things later rebound though.
Most slot APs I know do not ever talk about EV, only good or not good and the experienced ones know how to choose which plays they take based on total EV without it being known exactly. There are a ton of people who make way more than those more precise. Obviously for the reason the knowledge isn't special or exclusive to them, we're then all equal and those with better health and other skills make the most.