IMO: Moodle LMS is not very well optimized for selling online courses, but a slimmed down version of Moodle could be.
If you want to sell, or give away, online courses, you probably do not want a lot of collaboration with learners. Moodle is loaded with blogs, forums, chats, video conferences, and so on. Most of that would not be wanted.
Sites offering online courses are not interested in stuff like: attendance, scheduling field trips, how well students are fitting in, or anything like that.
Moodle gives a lot to students: calendar, blogs, storage for files, and more. Most of that would not be wanted.
Moodle has high hosting requirements compared to other applications, like wordpress.
Of course the unwanted features can be shut off, but that takes time and effort. And the hosting requirements are still there. Also, all the extra baggage (for online courses) just makes Moodle more difficult to use.
Just a thought.