You (2) is not correct. Most W3C specs are edited if not outright proposed by browser implementor teams. And of course nobody anywhere ever prevented browsers from shipping stuff under feature flags (most of ES6 was in Firefox since the days of FF3/FF4, with slightly different semantics, and with an opt-in behind a version flag for instance). Hixie (HTML5 editor, CSS Selectors Level 3 editor) works at Google since 2005 and worked at Opera before, Shadow DOM's editor is Google's Dimitri Glazkov
