To be honest have not made anything on HubPages. Who's fault is it? All my own I am sad to say. I am rather new to Hub Pages and while I have built web sites and used adsense in the past, I did not completely understand what I needed to do with HubPages to make money. Almost all of the Hubs I wrote so far had more to do with me and what I liked. I did not do the necessary research to find the niche products that people were looking to buy and did not really give them a good reason to click my ads. People must be looking to buy rather than just browsing something completely unrelated.
One thing I did notice about adsense, it is a total numbers game. The more traffic you generate the more chance you have of someone clicking on your ads. To make serious money you need massive traffic as demonstrated to me by using ad words in the past. The higher percentage of clicks per 1000 visits is known as CTR or "Click Through Rate. If you get 2 clicks per 1000 this will give you about a 1% CTR. The more clicks the higher your CTR will be.
Would it be nice to make money using HubPages, sure it would. But HubPages is so much more, it is a community of great people to interact with and collectively share so much great information. The money is just the icing on the cake, the cake is about having fun and swapping stories.