The C programming language might be a good example. From a modern perspective, requiring forward declarations seems like pointless busywork. At the time it was written, decisions like that made it possible to have a one-pass compiler, which was an important efficiency gain. You could reduce I/O and maybe save RAM.
Agree. Unfortunately , the users of even the new usable systems may be loath to take up these changes. Why? I guess inertia and priorities. My mind goes back to QWERTY v/s Dvorak and how it panned out.
The top answer on StackExchange alludes to this, too.
Sometimes the new system isn't better so there's no reason to switch... AFAIK, Dvorak is not better than QWERTY (despite claims to the contrary).
I worked in IT at a hotel company when they made the cutover from a 3270 based text system to an early 90's modern Windows GUI -- agents hated it, even with command shortcuts it was slower than the old interface. Training new agents was faster, but experienced agents were much slower.