Shouldn't it just be hobbies vs income? What makes playing video games a special case? I only mention this because any relationship you might find is probably applicable to any hobby.
I'm not sure how helpful knowing someone's income is when sampling user's from around the world unless you have some form of secondary data that helps place people on the same measuring stick
That and comparing my salary to people in San Fransisco is depressing at face value (but less so when cost of living gets worked in)
