The OP over-reaches in that PageRank is just a small ingredient in Google's ranking, which covers many other components from TFIDF score to anchor text features and yes, PageRank. Naturally, Google used PageRank as a differentiator
in its marketing, but technically. Bing has been known to use >150 features to score the relevance of a page, given a query, so one would expect Google to exploit a similar order of magnitude of evidence in its ranking.<p>> Yet, despite being acutely aware of the dangers of ad-supported search, selling ads was adopted as the primary business model of the new search venture just a few years later.<p>Google was successful as a superior search engine, pushing out AltaVista and similar, earlier alternative search engines and Yahoo!-style portals curated by humans. However, Google wasn't a successful business for quite some time.
Eventually, they adopted (some people would say "stole" - there was a lawsuit) Yahoo!-owned Overture's ad model, which changed everything. Yahoo! owned Overture, and Overture had a critical patent. Yahoo! made one critical mistake: they settled the lawsuit for relatively little money. The rest is history.<p>Now many people complain about decaying search result quality levels. That just means there is space for a new search engine, how exciting! The good news is it has never been easier and cheaper to start a full-text index of the Web and associated search. For about 50k (a Xoogler's estimate, not mine) you should be able to get going. Sites like Gigablast show it can even be done as a one-man show, which I would not recommend (to many complexities in "small" bits even HTML to plan text conversion, load balancing, incremental inverted index updating etc. - all requiring nowadays some specialist expertise in a game where you can't afford to reinvent the wheel because you don't know the scientific literature/state of the art). The one thing that is hard to get is initial user traffic. But I think HNers will be happy to give each new engine a try!<p>In summary, I think there never was an "age of PageRank". But you may say Google Web search is past its prime. Perhaps Google could change that if they wanted - it may be that it isn't much of a priority at the moment, hard to say (they are (too?) big now).<p>Edit: Here, I've interviewed Shadi Saleh, the architect of Syria's search engine (if you think it's impossible to get up and running with a small team):
<a href="https://irsg.bcs.org/informer/2019/07/syrias-first-web-search-engine-an-interview-with-shadi-saleh-2/" rel="nofollow">https://irsg.bcs.org/informer/2019/07/syrias-first-web-searc...</a>