Here in Norway we have a law for mobile carriers which is intended to prevent moats. It states that carriers must provide access for a "reasonable price" to other phone companies. It seems to have worked fairly well.

One could imagine something similar, that sure you can put your own movie or TV show on your own website, but you must also sell it to companies who asks on reasonable terms. So Netflix can make a movie but couldn't say no to say Plex if they wanted to buy the rights to show it on Plex.tv.

No, just media production companies on their own streaming service. There is no reason to pretend that billion dollar, publicly traded companies are poor college kids just trying to get noticed on the Internet for their quirky videos.