> There is also a chicken and egg problem of software being dependent on hardware, and hardware only being useful if there is software to take advantage of its features.

In the 90s, as a developer you couldn't depend on that a user's computer had a 3D accelerator (or 3D graphics) card. So 3D video games used multiple renderers (software rendering, hardware-accelerated rendering (sometimes with different backends like Glide, OpenGL, Direct3D)).

Couldn't you simply write some "killer application" for local AI that everybody "wants", but which might be slow (even using a highly optimized CPU or GPU backend) if you don't have an NPU. Since it is a "killer application", very many people will still want to run it, even if the experience is slow.

Then as a hardware vendor, you can make the big "show-off" how much better the experience is with an NPU (AI PC) - and people will immediately want one.

Exactly the same story as for 3D accelerators and 3D graphics card where Quake and Quake II were such killer applications.