I think the incentives are not there anymore. Before the rise of smartphones a competitor could have emerged and take users from Google. Yahoo wasn't completel

I think the incentives are not there anymore. Before the rise of smartphones a competitor could have emerged and take users from Google. Yahoo wasn't completely dead yet. Platforms were mostly open, a sea change could have happened (though highly unlikely). Into the smartphone area, other engines became anecdotal (bing just exists in the background), there is enough lock-in to not have to fear against direct competition, and the main focus becomes having users spend more time on the web, search more, instead of staying in native apps. That's were, if my memory is correct, they ditch language based landing pages and start fazing out modifier support and all the "power user" part of their interface. Fighting SEO scams becomes a waste of time when it has no real impact on wether user will continue to use the product or not.