Earlier quoted context omitted.
Why do we need a tipping point? Proposal: 1) Human progress arises from the development and improved use of tools/technology (and I'm including concepts like "if", as well as skills, as kinds of technology) 2) Our tool use abilities interact multiplicatively/geometrically. E.g., [what I can do with a hammer and a shovel] is not the sum of the [things I can do with hammers] and [the things I can do with shovels] 3) Ou…
I think language works as a tipping point in that sequence. For technology to interact as you say, it has to spread easily.
A more plausible hypothesis seems to me to be that language itself is constituted by a suite of cultural tools/skills. A language with a very limited vocabulary (especially one restricted to largely unhelpful words, e.g. "Justin Bieber", or "toe wart") is much weaker than one that has benefited from decades of cultural and generational digestion and iteration (i.e., a language that includes concepts like "however", or "on the condition that", or "art", or "gravity").