I do as well, and wish there were more research available on internet advertisingHave you actually looked? It's one of the most actively researched fields in the world at the moment.
Try http://www.iab.net/insights_research to start.
I'm sure a few companies at the top of the pyramid make money
This is absolutely, completely untrue. One of the reasons internet advertising is so popular is because its effectiveness can be proven - advertising companies can show how people exposed to ads buy at a higher rate. The improvement in rate can be calculated exactly, which shows the advertiser exactly how much they should spend.
Take a look at http://www.aimia.com.au/enews/IAB/IAB%20Retail%20Study%20-%2... (skip to roughly half way thorough).
There they promoted a new product in one market exclusively online, and did no promotion in the other market. Sales in the promoted market were 11% higher than the control.
Don't believe it? Try it yourself - I wanted to understand it better, so signed up for an affiliate account and did some Facebook advertising. It worked quite well - I was able to make around $15 for every $1 spent (obviously this was a very specific market segment).