In the 40's? By the time they would have had an opportunity to apply this to making a search engine, its unlikely that they would be in a position to drop everything they were doing and create a startup, assuming they would even remember the research they did so long ago and realize the insane value of making a search engine like that.
I think ruang was referring to Kleinberger, who applied the idea directly to web pages, as opposed to scientific journals or economies. He did it only short while before Page and Brin, and they even cited him. As to why he didn't make a search engine, I'm guessing it's because CMU is in Pittsburgh.
Kleinberg, not Kleinberger, and he's a prof at Cornell, not CMU. I'd guess it has less to with geography, and more to do with the fact that Kleinberg is a (brilliant, celebrated) academic who probably wasn't very interested in doing a startup.
