Consider: Terminal.app comes with macOS, not with Xcode. If the BSD environment was just there for developers, would this be true?
Today's Microsoft seems to increasingly think sysadmins would rather use PowerShell than MMC snap-ins; I'm inclined to think that today's Apple is similar. And there's nothing inherently hard about CLI interfaces; "regular people" used MS-DOS PCs for ~two decades.
I would bet Apple just thinks the CLI is the optimal Human-Computer Interface for doing some things.