Don't just disagree, provide information if you have it.
I think you were talking about Coursera's "specialisations," which are essentially a grouping of "signature track" courses with a project or exam at the end. All of the courses can be taken for free if you don't care about the special certificates, but the project is just for paying customers.
Udacity is running some "pay only" courses with Georgia Tech for its online masters program, too. Not sure about their other offerings, or about edX.
Ok I am not 100 percent sure about that but it does seem that some courses in specializations are only available in this way.
EDIT: ok, so you were apparently right. The specialization courses stay free, but it's not so obvious when you are looking at them from the specialization page.
If not, I guess we once again feel the pain of universities selling out their knowledge to commercial gatekeepers.