There is way more to it than that. A massive part of why Apple have been so successful is that their software increasingly runs on hardware they designed explicitly for it, and that integration has paid off - they frequently smoke the competition in performance per watt, and they are no longer beholden to Intel's roadmap to get features and functionality they need.
Imagine if they then had to get their operating systems running on an infinite variety of off-the-shelf components. How much buggier the software would be, how many features they would have to nix entirely or make exclusive to their hardware anyway, how poor the experience would be for users who were trying to run Mac OS on those cheapie laptops you buy from Walmart or Amazon. There are many benefits to not licensing.
I was alive for the last time Mac OS was licensed to third parties, and Steve trying to get Dell to license Mac OS. I personally think that was a horrible detour.