Except both Javascript and Python - along with a bunch of other dynamic languages such as Ruby and Elixir - are adopting gradual typing into the ecosystem. In both Javascript and Python, most of the major libraries and frameworks are either typed directly, or provide typings. It's difficult to get a good overview of the ecosystem on the closed source side of things, but most of the people I talk to in the Javascript world are moving pretty quickly towards Typescript, or have done it already.
But the key thing is that none of this is for performance purposes. Which is kind of the whole point of this talk: speed isn't everything, and the productivity of languages without types outweighs that of languages with types. But it turns out that types are really useful even without any sort of performance benefit, hence why a lot of languages are turning back to typing code without using those types at runtime at all.
Or similarly, he makes a point about how it's often possible to statically analyse dynamic languages, which is true, but it turns out that it's still so much easier to analyse statically typed languages that adding types back in often makes sense. If you read library documentation for packages using gradual typing, this is often one of the things they specifically mention as a reason for using their library with static types instead of without.
The point, as I understood it, was that you don't need static types to still get lots of cool things (performance, analysis, etc). Which is stuff I don't disagree with. But the quality of those things with (well-designed) static languages is still so much higher than it is in dynamic languages, which is why so many languages are now trying to support both modes.