Yep. Looks like you answered your own question. Of course the development of language with the coding and representational abilities even surpassing that of DNA was a big part of what made this possible.
I think it is intrinsic to the very process of life.
On the contrary, it has always been the most successful evolutionary strategy, especially early on in evolution. That is when you got real advances in evolutionary development.
Not only will you find symbiotic relationships in the earliest of ecosystems but the cooperation implicit in multicellular organisms was a key step in evolution. Any close examination of the human body reveals that we are literally built of cooperative symbiotic relationships. There are also hints that eukaryotic cells evolved from prokaryotic in a similar way by symbiosis and cooperation. And when you go to prebiotic evolution I think the cooperation of different chemical cycles was a key part of the formation of life itself.
NOW consider the implications of this. The old social Darwinist idea about society’s protection of its weaker members being an obstacle to evolution is revealed to be pure nonsense. Evolution is not even driven by natural selection as they supposed, but by variation. And society’s protection of its weaker members increases variation. We don’t all have to be Daniel Boones surviving on our own in the wilderness. We now take thousands of different roles in cooperative efforts which enrich everyone’s life. Thus instead of halting evolution this has greatly accelerated it, which is pretty obvious to anyone looking at how fast things are changing in the world.
But doesn’t more evolution mean humans changing into something else? Not necessarily. Eukaryotic cells evolved 2.7 billion years ago and they have not changed much in all that time. The evolution of all the different plants and animals all evolved with those same basic cells. Of course we do see a variety of cells in the body as they have adapted to their special roles and I suppose we might see some of that also, not by the evolution of new species any more than those different cells are different species but changes brought about by the abilities of the developmental relationships which we might call technology.