Earlier quoted context omitted.
How about not duplicating your post simply because the first one got downvoted?
Well to my defense, people seemed trigerred by my first sentence and then overlooked the proposal, that was my understanding. Thus I reposted without the sentence to gather a more useful feedback than dislikes.
As far as the proposal, you basically say Mozilla is petering out/an also-ran and that they should essentially leverage what can be leveraged from Chromium and focus on their custom functionality to differentiate and allowing them to focus in such a way that they don't need as many resources. You also invoke Not Invented Here, yet pretty sure Firefox predates Chromium by a pretty fair margin, but I would imagine that WebKit/Chromium/Blink all exist because the stakeholders of the time didn't feel Firefox was moving in the direction they wanted to go. If that's the case, what likelihood is there that Firefox is going to import more than necessary from Chromium effectively allowing Google et al to steer Firefox's direction? You bring up modules they do use, but those are essentially standards that they have in place because everyone should have them. Your "third way" is more or less what they're doing already, you even acknowledge this, but you advocate for a vague "more" for them to bake into Firefox. What more are you specifically wanting them to bring in from Chromium?