The competitive environment for affiliate marketers was created using aggressive tactics.
Challenging Returns.
The dismal statistics, seen in affiliate marketing, come from the 99% of people who tried to fund a "worthwhile" project. They used affiliate ads and failed. The majority of people who tried affiliate ads, as a get-rich-quick scheme, failed as well.
The Perspective of the Aggressive Affiliate.
A large number, of the most successful affiliates, use aggressive techniques. They are doing things like installing parasites on machines. Or, they use email spam. Or, they intentionally load up web pages, with keyword-rich terms but little content, to rank highly in search engine results.
To affiliates, the term "content" means keyword-rich steams of words. There are now affiliates simply grabbing meaningless streams of words to make misleading pages with ads.
Aggressive Tactics.
There are affiliates with massive databases of products (often the databases are horrifically inaccurate). They create millions of web pages to convince search engines they are meaningful.
Many affiliates do misleading things, like join a location-oriented datafeed to create misleading web pages. This is designed to catch people who do searches on a town name and a product.
There are other clever tricks. For example, if store X doesn't offer coupons, make a "COUPON COUPON, GET YOUR COUPON PAGE AT STORE X COUPON STORE X COUPON, COUPON" web page. It does not matter if there is no coupon. The keyword combo is what is important.
The Result.
A person looking for a bargain often ends up on a page using aggressive tactics. Next, load the merchant site in a 1x1 frame to set the affiliate tag. Badda-bam badda-bing. You get the commission and are off to don your white leisure suit in the local lounge.
Conclusion.
My guess is, for every dollar made by a site trying to do something worthwhile, $3 are made by affiliates pulling stunts. This includes using misleading datafeeds, misleading text, parasite programs or other practice. However, the results are clear. Using the aggressive tactic works!