Something that I noticed among those people who are involved with the various writing sites (Helium, Associated Content, etc.) is that a lot of people join them, write a couple of articles, then become upset when the money does not come flooding in. Then they post a complaint and leave in a huff.
Now, there are people who do not fall under this category. People who are willing to put in the time and energy to build up a stock of articles. These people eventually reach payout.
And as far as I can tell, these two types of people populate all the earning possibilities. Whether it is PTC, PTR, survey sites, social networking, etc. Either they expect instant success, or they are in it for the long haul. The same holds true for brick and mortar ventures.
In my case, I tend to assume for the writing sites that I will only earn a stack of pennies after I create a ton of articles. I am in it for the long haul.
I think that one of the reasons for this expectation is my experience with previous businesses. My father never made any quick money. And restaurants make mere pennies for their most frequently sold items. It is time and volume that makes up the profit, not a quick instant success. Or at least, that is the way it works in my universe.