> But it's not entirely clear to me whether we've fundamentally changed our nature, or if the tribes have just gotten bigger.
I think part of the reason for this lack of clarity is that we are going through this change right now. We're in the middle of it, with people at all ranges between "totally tribalist" and "totally humanist" (if "humanist" is the right term to use there, as in advocating for all peoples). Nationalism is one kind of pseudo-tribalism that is about more than just who your family is, and I'd argue globalism is another step along the path towards a less tribal society.
The other issue is that not everyone agrees that becoming less tribal is a good thing, so you have some people actively trying to speed the change, and other people actively trying to slow or even reverse it. So, yeah... it gets pretty confusing.
I suppose it comes down to how one defines 'human progress'. For me, the more relevant issue is how humans interact with each other (mostly at the non-individual level). I mean, we've mostly gotten past hanging out in small tribes, killing members of other small tribes in order to take their stuff. Arguably, we've made progress. But it's not entirely clear to me whether we've fundamentally changed our nature, or if the tribes have just gotten bigger.
So although I'd agree that technological progress plays a role, I think it's an indirect one. Technology makes resources more plentiful. In turn, this makes it easier to get by without having to murder anyone. But it's no guarantee that we won't. Indeed, we seem to be at our most inventive when some other tribe is trying to kill us and we're trying to do the same right back (i.e. during times of war)...