And that, is the primary problem with google results right now...they are artificially induced.
All of the information on the internet across all sites (mostly) is natural. Links flow naturally (mostly) from one site to another because they are inter-related as determined by the millions of publishers of countless sites. Not every site attempts to manipulate SERPs. But in google's unnatural attempt to craft results to meet their manipulative agenda they have to go against the natural flow of info. Hence so many exceptions in the code.
Yes spammers are a problem but in an attempt to be seen as "the bigger man" they egotistically go after spammers with nukes and wipe out all the legitimate sites along with them.
From what I see Bing returns very natural results with very little spam and in most cases it's highly relevant to the query -- of course there will be a few exceptions. So why has Bing surpassed google with good results? My guess is they aren't attempting to micro manage results to maximize profits. Google is digging their own hole but because they have become so dominant they are so large that it is going to take a real big hole to swallow them so we are stuck with them for a long time to come -- unless we stop catering to their crafting. We only have ourselves (webmasters) to blame for this ongoing nonsense by placing them on a plateau and stoking their ego by thinking that they are better than the collective sum of us -- they are not and never will be.