macOS isn't just a GUI translation of a UNIX environment, though (that'd be your average Linux Desktop Environment.)
macOS is instead a consumer-electronics abstraction layer for non-technical users, that relies upon and integrates with a UNIX backbone.
Which is to say: Apple (unlike Microsoft until PowerShell) has always assumed that the people who want to get fiddly technical stuff done, know how to use a command line. macOS's "power tools" are CLI tools. macOS's GUI programs, on the other hand, are for the 80% use-cases of regular users. They don't expose niche use-cases, because that functionality was already exposed just fine by a CLI tool, and power users can just use that CLI tool.
Another example of this: a lot of things that would be exposed as checkboxes in some arcane MMC snap-in in Windows, are just exposed as "defaults write ..." in macOS. Why bother building a GUI for a rarely-changed, technical setting, when the CLI is already a perfectly good one?
And yet they are removing command line utilities... High Sierra just removed 'telnet' and 'ftp'. Crazy that Windows ships with a telnet client (you have to enable it, but it's in the standard distribution), and a UNIX-derivative like OS X doesn't.
So? 99% of my use of ftp or telnet are for internal network use. And if I must telnet somewhere, I know to use a tunnel. Or my traffic doesn't need to be encrypted.
Why not remove netcat, as well? It opens unencrypted sockets. Or perhaps wget, since it lets you download unencrypted http? Even git has a built in ftp client.
There's nothing at all obsolete about ftp or telnet. They both implement their respective protocols fully and properly.
New devices shouldn't implement ftp or telnet, but that doesn't mean that having the ability to connect to them is no longer something that happens.
macOS is instead a consumer-electronics abstraction layer for non-technical users, that relies upon and integrates with a UNIX backbone.
Which is to say: Apple (unlike Microsoft until PowerShell) has always assumed that the people who want to get fiddly technical stuff done, know how to use a command line. macOS's "power tools" are CLI tools. macOS's GUI programs, on the other hand, are for the 80% use-cases of regular users. They don't expose niche use-cases, because that functionality was already exposed just fine by a CLI tool, and power users can just use that CLI tool.
Another example of this: a lot of things that would be exposed as checkboxes in some arcane MMC snap-in in Windows, are just exposed as "defaults write ..." in macOS. Why bother building a GUI for a rarely-changed, technical setting, when the CLI is already a perfectly good one?