The major takeaway for me is that with a strongly held culture, everyone in the company is playing the game by the same rules, making it clear how to succeed, how to fail, and as such, how to conduct business. It's also clear whether or not you would enjoy working there -- there's no finding the right team or department with its own culture if everyone has the same culture there.
Of course, he doesn't explore whether or not the benefits of this are worth the disadvantages, and there's plenty of room for argument either way, especially with large organizations.