Back in July, Google's work on a Web Integrity API emerged and many equated it to DRM. The company announced today it's not proceeding...
The Chrome team says they're not going to pursue Web Integrity but...
it is piloting a new Android WebView Media Integrity API that’s “narrowly scoped, and only targets WebViews embedded in apps.”
They say its because the team "heard your feedback." I'm sure that's true, and I can wildly speculate that all the current anti-trust attention was a factor too.
The most likely option is that they will rebrand and we will have to push back against a "completely new, completely different functionality" in a few months.
I mean, Widevine is present in all browsers and actively used by Netflix for example. YouTube also uses this when you're watching movies on YouTube Movies.
Not running DRM on the majority of YouTube content is also likely due to the added cost of running such encryption (the encryption is usually on a per-customer level, not one key fits all) and the added bandwidth and computer cycles required. Not to mention that this might be a legal struggle with the content creators.