why did something like Google not emerge earlier in the web’s history?

A really interesting question from Finn Brunton’s Spam pg 218:

An interesting question can be raised in relation to this innovative development: why is it innovative—or rather, why wasn’t such a system already normal? Citation analysis has been a common tool in social science since the Science Citation Index ® began in 1963 (with the original outline of such an idea in 1955, in Eugene Garfield’s “Citation Indexes for Science”). Some of the conceptual elements of such a system can be found as far back as the 1873 publication of the first Shepard’s Citations, which mapped legal citations. So why did such an approach only appear with “third-generation” search, rather than at the outset? Was it the conceptual understanding of the web in the initial years of browser development—that is, did the web not look “social,” at first, in the way a citation system does? Was it the separation of different disciplines within academia and business, such that the engineers, programmers, and entrepreneurs of the early web did not have a range of theories with which to analyze their project?