I agree that removing/limiting access is lousy by Coursera and Udacity, for courses that used to be free and contain valuable fundamentals.

I don't agree that the golden age is necessarily over though. The MOOC space is getting crowded, just look at all the offerings at https://www.class-central.com

MOOCs by government-backed traditional universities from Europe / Asia is taking over a large chunk of the "market" meaning that Coursera, Udacity, etc. is finding it difficult to get any returns.