so the underlying assumption behind most every post here is that the only way to 'contribute to society' is to take part in the production-and-consumption market economy.
Nobody, until now, has mentioned consumption. I'm not sure how you got that from "most every post here", but you seem to enjoy reading what you want to read.
(don't worry, you're not alone, it's a popular characteristic around here)
meh, if it makes you (and they) feel better who am I to say otherwise?
If you're helping the people paying your way then you're not a drain.
Actually most of us included (some) other kinds of productive activities in our definition of contributing to society.
A bit defensive isn't he?