Google has been de-emphasizing link quantity in their algorithm for almost a year now. They now focus on quality and authority of links. You should be seeing a drop in those other companies who participate in link building schemes, UNLESS they employ other strategies that hold SEO rankings. Content posted often (doesn't even have to be good content), relevant search terminology that matches closely with consumer entered terms, etc will influence the ranking more than links. Now the Google+ is becoming a big factor, link building is just another black hat option that has seen its better days.