This raises so many questions that I can't even really comprehend that it worries me. Please, if there are well formed responses or dialogues that form based on this, somebody make sure to link them back. Very very interesting read.
Google and Facebook need cluster computing solutions like MapReduce and Spanner. You most likely don't, and are years away from needing one. Even a successful startup like SnapChat or Tinder could probably do all their analytics/graph processing needs on a single core. So worry about the other things first.
There is a similar section in Knuth's Stanford GraphBase where he examines several graph algorithms and finds that the more advanced ones have better asymptotic behavior, but that the simpler algorithms outperform them at real numbers.
Bearing that I am not an expert, I do want to know of more in this discussion. And I fully welcome explanations of where I'm wrong. :)