It is not so much about the amount of hubs, but rather their quality and subject matter. If you are under the Hubpages ad program, then you will earn from traffic (and in my opinion this is steadier). For the hubs, when you start one, there is a guide to targets that are worth achieving ... such as full size photos, 1250 words, video, poll etc. Keywords are also very important, as is meeting a need/want with your article. If it is interesting or useful, then it is more likely to be shared with others.
However, depending on your niche, you may or may not get traffic to an article. To give you an idea, I would say that 1000-1500 visitors a day will net you $4-5. It will take a long time to reach that, but once you are there, it will continue normally. Articles also take about 6 months to age, so ones you write now may not get traffic, but in 6-9 months could suddenly be your most popular ones.
If you want more tips, I have written a lot about this. My 100th Hub shares many tips too. Hope this helps and good luck.