I'm somewhat surprised by this sentiment, but I guess it's relative to what you consider to be "not...much money". I'm not making a whole lot, relatively speaking, but it's great money considering that I'm earning money doing something I love. Moreover, it's passive income in that the work I do today can earn for a long time to come. (In fact, I've got a couple of hubs comparing my income from HP against a couple of other sites.)
Basically, I think hubbers have to be active and stick with it. I keep hearing that you need about 100 articles/hubs/what-have-you before your income becomes something worth talking about. That being the case, the answer is to keep grinding and putting out unique, quality content.