Additionally, most advertising are about pushing people to buy product like snacks, beer or cloths. I doubt many people really install a Zara or Gap app or put the website in their bookmark.
If we assume that different search queries are better served by different engines then I wonder if it's not possible for someone to develop a "thin" search engine that would do semantic analysis of the query and then redirect it to one or more sites, or show results side by side...
http://venturebeat.com/2015/12/22/google-is-reportedly-devel...
This is why I have mad respect for Zuckerberg. He's willing to place gigantic bets (Instagram/WhatsApp) when and where it matters.
Convenience trumps accuracy and people want a list of offers they perceive to be competitive, not a list of search results. Millions of people look on Amazon first, or Cheapoair, or Hotels.com, the list goes on.
Whats more likely to happen is that someone will come along with better search with less advertising (just like Google did), or someone might build a better social network with less advertising (just like facebook did). There's as much precidence for these things reoccurring as there is for users increasingly searching rather than using the url bar.