That was a poor choice of words on my part. Rather I meant, they themselves stated it was not feasible for them to keep up using EdgeHTML and they could not. The same may be true if they were to completely fork Chromium and maintain their own version (ala Blink from WebKit) while keeping up with the changes made by Chromium that in turn propagate to the entire open web due to its dominance. It’s the reason they moved to Chromium and contribute back upstream rather than “fork” it.