And if they focused on the UI at the expense of everything else, they'd throw out a different section of the market. There are other tools out there with nicer UIs but they are not as flexible or powerful as KiCad. If the UI is that important to you then I suggest using one of the tools that has a more polished UI. The rest of us have managed to work around the UI issues in KiCad, it's just not a big deal.
I've used at least 5 or 6 different EDAs and they all had lousy interfaces, even one that cost thousands of dollars. KiCad is free and it does the job. Frankly I'd be annoyed if the UI changed significantly at this point because I'd have to spend time re-learning how to do things, time that I could instead spend making more boards.
Most of them have, that is correct.
But it's not a good argument to (therefore) do the seem thing.
At least with most other EDAs the user can change most of the interface to their liking.
And with most of the competitors the user can choice to work mostly with just keyboard shortcuts or only with the mouse or an hybrid..
This is fixed in KiCad and even many icons for certain tasks are completely missing.
Besides, if you read the KiCad 6 roadmap they even admit that the interface is not very logic and inconsistent.
I know it's not a very popular one anymore, but Ultiboard/Multisim is pretty good with their GUI
Easy to learn in just a couple of days and fully customizable.
I find it a bizarre way of working, the other way around.
Technically speaking an interface is also not the most difficult to program.
Like I said before, just basically copy what others did and improve/make it your own from there.
I find it cute to read that the current KiCad users really think they are a significant and representative amount of "the market ".
To be clear, I am not just talking about my personal preference, but what works for many people.
In a sense EDAs always have been very conservative to this compared to 3D CAD software, things like video editors or other sophisticated programs.