Rebol was an attempt at grappling with the problems of overly complex and bloated software. Part of that means not wasting RAM or CPU cycles.
Optimizing is just a normal part of software development. It's not done to please the programmer, but to build something of quality that respects the user who is running other pieces of software that are also using resources. Think of it as being a good computational neighbor.
There needs to be some thread here about "computing horror stories". A month ago there was an article on Hacker News about NixOS and it's packaging system. As some Nix user had just contacted me about packaging xu4, I thought I'd give it a spin. After downloading the ISO and installing it on a virtual machine I went to get a package listing...
and was greeted with some vague error message.
It turns out that the package manager was using well over 1GB of RAM and simply crapped out because my VM didn't have enough. Some NixOS user told me:
"Listing all packages is a bit of a weak spot. The entire package set is described in a lazy, functional language and listing or searching it requires evaluating the entire thing."
This is an entire OS custom built around a package manager, and it couldn't even give me a listing of my packages. The Nix developers want to geek out about their language, but I just want tools that work.
Thankfully, data-oriented design is now a thing, so I know at least someone is paying attention.