we don't need variety of engines, we need a non-pofit alternative to google that can throw a punch, which firefox is.

An engine is a technical undertaking (of enormous proportion), and there's essentially no need to have even more of them. If anything it'd just make building websites harder. The issue isn't with blink or gecko it's with Google's control over the browser space. If Firefox was built on blink and had 50% market share I'd be happier than having a hundred engines with 2%.