Earlier quoted context omitted.
No, blame the movie studios, record labels etc. They're the one which require asinine DRM support for web browsers. Google/Microsoft/Apple/Adobe want to support media content, but to do so requires towing the line with the media companies otherwise they refuse to license the content (at least in HD+). Having worked with various DRM teams I know that they have to treat their code as if its the most secret code in the…
I'm pretty sure some method Netflix uses is broken anyway. People don't seem to have trouble uploading 4k rips to Usenet. (Though I haven't actually checked recently.) We were sold DRM as "the evil legacy studios are evil and make us use DRM". Well, now that Netflix produces their own content and it's still DRM'd... I guess that isn't really the reasoning.
In the rare case of content that is actually made by Netflix, it’s easier to just put DRM on it, because otherwise every system dedicated to encoding and playback would have to have a code branch that was special for non-DRM content. It would be a maintenance nightmare. It’s a lot easier to push all content through the same pipelines.