I really doubt *nix would have made it so far if the cli were audio based, too. It's a fundamentally slower and lower bandwidth communication channel.

*nix was optimized for low-bandwith channels. That's why the command names and options are extremely terse and typically return trivial output on success. OTOH it was assumed that input would be reliable, so there's no confirmation required for potentially dangerous commands. A "*nix for voice" would need to address that, at the very least.

I’d sure be lost if I had to listen to the entirety of a manpage or flesh output or /var/log/messages read out by voice. Some of those could take hours to read out. Nothing actually trivial about *nix command output. Just sometimes terse.