Software as a list of requirements and that's it. The local LLM appliance everybody has taking in a document specifying hardware, interfaces, and requirements and spitting out software changeable locally via conversation with its users.
In the same way you have a cookbook with recipes to make dinner instead of ordering out.
For that, you'd want the list of requirements and hardware documentation to be written in a precise, formal language. That's no different than writing them in a programming language (though a declarative one, instead of the more common imperative ones).
I've in the past (way before LLMs existed) thought about automatically generating device drivers from hardware documentation. But besides the need for very precise documentation, hardware never works exactly as documented; a human-written device driver can avoid problematic areas (perhaps even by accident), while a computer-written device driver would end up exploiting every corner case of the documentation.
There is quite a bit of distance between the exactness of any human language and an sort of programming languages. When you have a language model loaded with software engineering best practices you do not need the exactness of a programming language to describe desired behavior.
Hardware documentation is indeed often lacking in plenty of ways but in a world where writing your own software through agents is commonplace, the hardware manufacturers (or the community) would make testing that documentation to find the problems an important part of hardware development.