Is Google's search relevancy job tied to one person?

How is the information relevancy to Google consumers calculated when a Google search is performed? Google would have you believe that an automated algorithm computes all these variables to ensure search results are tabulated perfectly during every Google search -- and consistent relevancy is key based on specific words, word combinations and actual phonetics of the way each search if performed.

All these searches result in a quantity that boggles the mind -- it's to the tune of hundreds of millions of searches per day in many different languages, with each result appearing in an uncannily sub-second speed in many cases.

So, who or what determines the programming that allows Google search results to be as relevant and useful to the Google searcher? Who tweaks the programming constantly so that relevancy is fair for all against those who would want to appear everywhere they can on the Google network, regardless of relevancy? Apparently, this effort is headed by Google employee Matt Cutts (which seems odd that only one person is in charge of anything at Google).

This web post points out that Cutts' extended vacation has shown itself in reduced relevancy of Google search results, although without specific examples and a statistically-significant sample, this is all just hearsay. Google insiders -- is there is kernel of truth to this alleged issue? Customers and investors want to know.