I think this article is missing the point a bit.
It's saying that the action of calling an async function (e.g. one you've written) isn't itself a yield point. The only yield points are places where we the call would block for external events like IO or time - `await asyncio.sleep(100)` would be one of those.
This is true, but surely fairly irrelevant? Any async function call has somewhere in its possible call tree one of those yield points. If it didn't then it wouldn't need to be marked async.
I believe Wayland (don't quote me on this because I know exactly zero technical details) as opposed to x is a big step in this direction. Correct me if I am wrong but I believe this effort alone has been ongoing for a decade. A proper sandbox will take longer and risks being coopted by corporate drones trying to take away our right to use our computers as we see fit.
All programs in X were trusted and had access to the same drawing space. This meant that one program could see what another one was drawing. Effectively this meant that any compromised program could see your whole screen if you were using X.
Wayland has a different architecture where programs only have access to the resources to draw their own stuff, and then a separate compositor joins all the results together.
Wayland does nothing about the REST of the application permission model - ability to access files, send network requests etc. For that you need more sandboxing e.g. Flatpak, Containers, VMs