Fun exercise I guess. I agree with dragoncar though, I think this is quite optimistic.
This is hard to guage. Look at the link provided. 1,001 votes, and that's a huge voter turnout based on most of the other polls I've seen around here. I think the biggest variable in your thought experiment is the 100,000 MMM readers and their NW. I would wager the average reader would fall extremely short in the NW category than the average active forum contributor. Who knows?
Just for fun I extrapolated that poll into some real numbers. A few caveats:
1) The poll is 2 years old, so much of the data is stale.
2) The poll is flawed (mandatory complaint for Dragoncar and Rebs) as there is no category > $1M.
3) I used the highest possible NW for everyone in each category, so $100k-$250K I used $250K for everyone.
4) For anyone that answered > $1M, I used $2M as an average.
So if you take 73 members at -$100K, 69 members at $0, 242 members at $100K, etc., etc. you end up at $478,650,000. That's quite an impressive # for 1,001 people, and it averages out to $478K per member. Not bad.