I don't even think it is Google, Microsoft, and Netflix. It's the media companies and film studios, which demand protection for their valuable products. When Netflix signs a license for a film or show, even its own, this license certainly says that is has to be copy protected, like with Blu-ray discs.

I also don't get much of the argument of the EFF. A browser which doesn't support EME can't use sites which require EME, like Netflix. Maybe my English is bad or the text badly written.