I have a hub that was hit 10,000 this week - almost 30,000 all toll, but each day, I don't even realize $1.00 in earning. My ads are set up and I can see them on the page. I have checked all my ads settings. I am baffled because this is my most successful hub.
It is hard to tell what will happen after a Google update. Sometimes there is an initial loss of traffic followed later by a recovery and sometimes even an increase in traffic. The bad news is sometimes there's no recovery. I'm afraid a Google algorithm update has to be waited out. Then followed by relief or, possibly, working on articles to make them google-friendly. Or whatever it takes to recover.
Oh, shoot, I misread your question. The only thing I can guess is that those are not human visitors or visitors from somewhere where advertisers will not pay much for. Or the CPM is really low. Somehow the ads are not paying as much per view/click. Or a glitch.
Edit: In other words, it has to do with traffic quality, possibly, or nature/cost of ads.
So you're saying you have lots of page views, but not the earnings you'd expect.
Are you using the HP earning program or AdSense on its own?
Remember that 40% of ad impressions go to hubpages. So if you got 10,000 views, approximately 4,000 of those you won't earn anything from. The normal range of earnings per 1000 views is $1 - $5, so for 6000 views you could expect to earn anywhere between $6 - $30.
Based on the last time, this hub was hit - the results are inconsistent. I do thank everyone for their response, however, I think this may explain it: "Processing Delays - HubPages Ad Program We recently partnered with a few new ad networks that have inconsistent report update times. Because of this, Ad Program earnings will arrive later than usual going forward. We will do our best to have the data updated as soon as possible. Thank you for your patience!."