I think that typically sysadmin-type people seem to have less customization, possibly because they ssh into so many boxes and dotfiles don't usually carry over.
It's a really simply, bare bones, kinda setup. Many spend hours, weeks, months, if not years tweaking their setup. Everything from the shell to their editor get "riced up"[1] just the why they like it. It's usually beautiful to look at, but if like me you work on a large number of servers each day, it's kinda pointless, unless you insist on cloning your setup on each of the thousands of servers in your company. Personally I configure almost nothing, everything is standard. I do load a few Vim plugins for syntax checking, but that's about it. I don't even care if something is zsh, ksh or bash, I just care that it's not sh, csh or tcsh.
The most customized thing I have is my ssh config. I'm sure I'm missing out on a ton of nice features, and I sometimes regret not learning tools to a larger extend, especially when others shows neat little shortcuts or speedy functions, on the other hand, I don't want the hassle.
I feel like there’s a sweet spot where I spend most of my time in a terminal but on a relatively small number of different servers, and that’s why I want things customized just so. It’s worth it because the number of machines is small.
