Sure, everything can be hacked into a video on the web. But luckily that makes your web page unusable, unaccessible, and also un-SEO-able. It would also require you to have expensive DRM authoring tools to have you actually create DRM signatures (it's not just a switch you can flip on). Let me rephrase: EME can only be practically applied to actual audio and video.

The point still stands. EME has been commonplace for three years now. If the fear that it would grip beyond audio and video in the real world is based in reality, we would have seen it by now. The W3C decision changes nothing for the people who would use it.

Yep, but that's absolutely what's going to happen. People love to put square pegs in round holes. I'd be surprised if most things weren't DRMed within 5 years.

I don't buy it. People could DRM up the internet - including text and images - much more easily - for years with Flash and Silverlight. People could use the everything-is-a-DRMed-single-frame-video-now hack since 2014. Neither have been a problem. I've never even seen the latter happening, even as a proof of concept (although I suspect someone will point me to one shortly).