Complacency? Google has such a dominance in search that their name is used as a verb. Combine that with their culture of automating everything to an extreme degree. And the end result seems to be: search that is just good enough that people keep using it and requires little human fine tuning/curation making it cheap at scale.
Not to mention how flawed the current search tool really is. If you search for something, page 1 shows results from page 7 to some infinite number. But click on that large number, and you find out that the last page was page 3.
