atlrus - 1:44 pm on Sep 12, 2013 (gmt 0)
As I pointed out above, big brands may not have the upper hand per se; they may simply benefit from characteristics that "big brand" Web sites tend to have, such as inbound links, massive numbers of pages, heavy original text content on pages (in Amazon's case, thanks to user reviews), how they rate in user testing, and so on. To borrow a popular phrase, "correlation isn't causation."
However, big brands like Amazon, yelp, ebay, etc. have had those "characteristics" for a long time, yet it's been only recently that they overwhelmed the search results. Which means that Google did something to tip the scales that way. It's not correlation-causation, but action-reaction.
As far as Google statements - I usually don't care too much about what Cutts says. For a long time Google appears to be trying to distract people from major issues by focusing on miniscule ones. One example is the disavow tool. Instead of focusing on why websites get punished for links out of their control, they introduce a distracting and time-wasting placebo "tool".