A lot more sites are getting hit that were building links for SEO purposes primarily, as opposed to traffic and branding.
I was more trying to describe the sites that have fallen versus dubbing anchor text as the reason. Not sure what the reason was exactly, but companies optimizing and showing little restraint with how they used anchor text, the sites they got links on, etc. all got hit.
In my niche it honestly looks like Google had a team of a 100 people look at every website's backlink profile and make a determination about whether they were gaming the system.