Another thing to consider about the number of traffic to our hub is: Where did the traffic come from? Is it from the within the hubpages community or from the SERP?
I have a hub that had a lot of traffic one day but I didn't earn any because all my visitors came from within the community.
Just giving you an idea: I have one blog site that has 2,000 to 3,000 views a day and can it gives me 10 to 15 bucks a day from adsense. I cannot live on that so I built a lot more, though not all of them earn the same amount but they help each other to give me reasonable revenue for the day
The idea is the same with our hubs we need lots of traffic and lots of quality hubs. But we still don't know how many hubs to make and how much we can earn because it depends on the quality and not the quantity. We will know it after we will see the result.