Absolutely the case; big name sites rule the search results. This seems to be what quality looks like to Google.
Google has long suffered from an algorithmic solution that identifies the best content for a given query on a page level. This is evident in each algo tweak that Google makes that apparently dials up the value of domain name authority, which further distances the best content from the brands that appear at the top of the serps. In fact, domain name authority has gotten so bad that scrapers can easily copy content from weaker/penalized domains and rank it rather quickly.
I think part of what we are seeing in the serps is Google's focus on penalizing instead of rewarding content. By introducing panda, penguin and other penalty based variables into the algorithm, content is no longer king and domain name authority is. I suspect that big brands get a pass on panda and penguin, which is why they are continually climbing in the serps with each update.
Thankfully Bing traffic seems to be improving, and their conversion rate is nearly double that of Google. I suspect Google's actual logged traffic is enhanced with excessive scraper/bot activity that is not as profound in Bing.