Effort doesn't relate to amount earned, otherwise the players doing missions would be earning the most money (anti cap missions can be a pain without the right ships).
Player interaction is what counts. Traders go all across sirius and have more opportunities to interact than miners sitting in one spot. Yes, perhaps you are more vulnerable when you're stationary in one spot, but a trader also becomes a target everytime he enters a trade lane / cruises towards a jump hole (ie, a lot of the time).
60m an hour is obscene, even if it "can't be kept up for long". The mining in Omega 49 was nerfed simply because it was an anomaly in the system, just like the Diamond/Niobium trade route.