Extension implies that the protocol is missing some capability, otherwise it wouldn't need to be extended. So we need to make the protocol better so they have nothing to add. If we don't add those capabilities, ever, then the protocol is doomed to eventual irrelevance and wasn't worth fighting over anyway.

Again, another thread where two billion people joining our network and meeting us where we are ... is somehow bad. If embrace extend extinguish is really the worry, then we have a bad protocol that needs extension to be usable by those 2B people, and we should fix that.

Am I living in a different planet from the rest of the commenters here? We have much more to gain from this than they do.