Well - since we're going to stay in the realm of speculation and Ive had a few too many - here goes:
They are not straying from this model whatsoever - they are -if anything- going closer to this model where authority sites and recip linking are the strongest model out there - there used to be a name for what you are seeing with these rolling updates - which are just test filters they are trying to adjust (which was confirmed by a Google engineer) - the name was everflux - for some reason a lot of people that are newer to the SEO (if thats what they call themselves) game havent seen this effect as blatent as it used to be, until the recent updates - so they are surprised by them - that is the only fact I can find in all of these threads.
The fact that there are so many automated spam models performing extremely well just goes to show that the filters are not having the effect Google would like them to have, and they keep trying to increase the settings - without testing first - and it has an effect on what some here think are "clean" sites because of the non-tested results. Then everyone runs around like chickens with their heads cut off proclaiming that Google has done some dasterdly deed and that they sun wont come up tomorrow - when all along - they just got to see publicly what Google has done all along behind the scenes
