Of interest may be my project that implements a CLIM-based user interface on top of Maxima. It turns out that CLIM is perfect for this, as its idea of presentation forms matches the way mathematical expressions are represented in Maxima.
I have made a few videos showing how it works. It's also available on Flathub, or if you're brave you can build it yourself.
I love CLIM, too bad it's not used much. The whole idea of it is very interesting, an evolutionary dead end that in many ways seems far superior then what "modern" GUIs provide
I think there are more practical reasons why it's not used more. What you say is absolutely true of course, but the bigger issue is that McCLIM still has some technical issues.
What is really needed is a multiplatform backend that implements everything completely. Right now the only production grade backend is the CLX one, and even that one requires you to jump though hoops to get complete font rendering.
I built all of this into the flatpak distribution, but few people are willing to go through that just to distribute some software.
I have made a few videos showing how it works. It's also available on Flathub, or if you're brave you can build it yourself.
https://peertube.mastodon.host/videos/watch/df751bd5-5a26-44...
https://peertube.mastodon.host/videos/watch/b003360f-97a9-4f...
https://github.com/lokedhs/maxima-client