You need links as well. "Sure, but good content will naturally be linked to", but then ask yourself, when was the last time you gave something you liked a dofollow link on your blog? And even if you did, you maybe gave one link for every 100 you enjoyed but didn't.
People very rarely link to things these days, and the big guys will pay people to provide links. Guest blogging was previously the ethical way to get those links until people started abusing it.