But nobody is using your hypothetical "structured CLI-based --help-equivalent consumable by LLMs and shell completion engines alike" either. In terms of mindshare, you're starting from scratch either way.
I just remembered docopt, which maybe fits the bill in a more Unixy way, but it and its ports are mostly abandoned, for various reasons.
Not in any meaningful, general way on Unix systems it doesn't. Nobody uses psh outside Windows
But nobody is using your hypothetical "structured CLI-based --help-equivalent consumable by LLMs and shell completion engines alike" either. In terms of mindshare, you're starting from scratch either way.
I just remembered docopt, which maybe fits the bill in a more Unixy way, but it and its ports are mostly abandoned, for various reasons.
Maybe they should consider using it.