The reasons are complex, but big business interests certainly are the driving force behind Common Core. You might find interesting my short column here:
http://www.aberdeennews.com/news/opinion/marmorstein-villains-are-clear-in-common-core-dramedy/article_5ba4678e-5dfb-5a8a-b99a-37d66efd678d.html
Good column. Thanks for sharing.