I joined reddit in 2007 but I'd been surfing it for a year or so already. Early reddit was amazing. There were no subreddits yet, which was fine, there weren't that many users. The concept of subreddits was innovative when they introduced them, but once you could create your own it was pretty mind blowing.
I always felt like reddit was "hiding" from the common folk. It had a plain white background with default blue & purple links and it looked like someone's personal project. Digg had lots of gradients and borders and glitz but reddit had a real "function over form" quality that really appealed to me as an engineer.
It makes me sad to think about how many terrible things it's been put through by its dumb ding dong owners over the years.
I've been using Linux since ~1996; I used to wonder about this a lot.
The tl;dr answer is, it's too much effort only to solve the problem of making life easier for new users, and it can be a disservice to users in the long run.
As others have pointed out, there are limited GUI tools for common administration roles.
Power users are much, much faster at doing things via CLI. Most administrative tasks involve text file management and the UNIX userland is exceptional at processing text files.
A graphical tool would have to deal with evolving system software and APIs, meaning the GUI tool would be on constant outpatient care; this is counter to the UNIX philosophy which is to make software simple and well-defined such that it can be considered "done" and remain versatile and flexible enough to live for decades virtually unchanged.
It wouldn't be that much easier for things like network rules unless a truly incredible UI was designed, and that would be a risk since the way that's implemented at the system level is subject to change at any point. It's hard enough keeping CLI userland tools in sync with the kernel as it is.
It would need to be adaptable to the ways different distributions do things. Administration on CentOS is not always the same as it is on Debian.
And ultimately, the longer a user spends depending on GUI tools, the longer it will take them to learn and become proficient with the CLI, which will always be a far more useful skill to have. You'll never learn the innards of containers or VPS' if you only know how to do things from the GUI.