I have a couple of issues with this post, even as I appreciate the confidence with which it's stated.
First, mount, whether back mount or top mount, are positions. They aren't techniques. Technique is how you transition to or from these positions, or how you attack or defend yourself while in these positions. Passing guard is a technique. Attacking the neck or shoulder is technique. Being in the top mount or back mount is positional.
Second, how are you defining dominant? I agree that back mount is a dominant position, but I don't agree that it's more dominant than top mount. What's the rationale behind your "bold" statement?