Speaking as someone who has never used it but has spent some time researching it, the Bloomberg Terminal constantly undergoes UI changes, though not in a dramatic way. It's obvious if you look at screenshots throughout the time (it even had some gradients!). It has had its own "rewrites in Svelte", transitioning from a custom renderer to HTML/JavaScript.
But you're correct - they don't mess with it, they slightly and mostly invisibly improve it, and someone who learned it in 80s could use it without problems today.
> the Bloomberg Terminal constantly undergoes UI changes, though not in a dramatic way
This is correct. (Source: I worked on Bloomberg's UI change management policies.)
Despite dismissive comments from design industry folks and more modern-looking competitors, the folks who ran Bloomberg's UX team maintained a focus on customer needs and user research. There are even a few cases where function teams went back and re-implemented old "bugs" after a rewrite (e.g. in the MSG editor) because users had adapted to the old behavior. (Thankfully nothing as bad as spacebar heating https://xkcd.com/1172 though)
> and someone who learned it in 80s could use it without problems today.
That's the true dream. Like all of those old movies where the hacker or fighter pilot has to use some foreign, alien or futuristic tech and they just use it!
But you're correct - they don't mess with it, they slightly and mostly invisibly improve it, and someone who learned it in 80s could use it without problems today.
https://www.youtube.com/watch?v=uqehwCWKVVw
https://www.bloomberg.com/ux/2017/11/10/relaunching-launchpa...
https://www.bloomberg.com/company/stories/how-bloomberg-term...
https://www.bloomberg.com/company/stories/designing-the-term...