The reason Yahoo didn't care about a technique that extracted the full value of traffic was that advertisers were already overpaying for it. If Yahoo merely extracted the actual value, they'd have made less.
One of the weirdest things about Yahoo when I went to work there was the way they insisted on calling themselves a "media company." If you walked around their offices, it seemed like a software company.
"By the time we were looking at Flickr, Yahoo was getting the shit kicked out by Google. The race was on to find other areas of search where we could build a commanding lead. That is the reason we bought Flickr - not the community. [...] The theory behind buying Flickr was not to increase social connections, it was to monetize the image index. It was totally not about social communities or social networking. It was certainly nothing to do with the users." (source)
"I spent years at Yahoo trying to signal the alarm that Facebook was going to take over the adult market unless we stepped in and used our existing social networks to fight back,"(source)