The talk is more about the web as an application platform, and its values, coming down to OS userland. Whether that means JS or Wasm or both doesn't really matter.
The talk predicts that Js will be dead (for user space) the moment it conquers the OS. Dead in this context means it will be invisible to the app developer just like C.
Highly encourage everybody to watch it and how people may interact with JavaScript more and more through things like WASM. Very funny talk too :)