Your calculations are 100% off. Most posts never get seen or they get seen for first hours. That is the earning time. Basically after 24hours there will be no big upvotes or anything like that. So there is no point of calculating per month, per year.
It's impossible to calculate how much one post will earn, since it depends on way to many factors.
Yes, I was assuming that the earnings were always constant! I mentioned it in the post! Oh, and for that post specifically- of course not everyone is going to make that much :) I wish though ...