I'm not sure what decoupling means, and whether it's of any technical significance beyond bragging rights, but chromium won't support drm out of the box either

I'm not sure what decoupling means, and whether it's of any technical significance beyond bragging rights, but chromium won't support drm out of the box either because widevine is obviously not a part of chromium. You can take the widevine library from chrome and make it work with chromium if you jump through some hoops.