I don't think it's even just that. If any of these companies did usability tests they'd discover quickly enough that their designs don't work. I guess they just don't bother.
I have worked in software development since the mid 90s, often freelance so I've probably been at 20-30 companies in total. All of these companies produced software that had some sort of UI. I think only a single time was any usability testing done, i.e. get a normal person sat in front of the software and get them to perform a task and see if they can figure it out on their own. Normally the process is that the designer asserts that this particular way is best, and that's the way it gets implemented and that's what the customer gets to use.
Part of the problem imo is that everyone thinks "how hard can it be?" and that they have good ideas for UI design. They therefore aren't interested in reading Cooper or submitting their brainwaves to even peer scrutiny.
What does that mean? (Not a native speaker)
Don't Make Me Think is another good book I think :-)
The UI on most mobile devices are terrible in one way or another. There are zero discoverability, things will hide, lock, block or disappear with no clear way of getting back.
Often I feel it’s easier to go to the computer. As an example: I cannot use the banking app on the phone anymore. In an attempt to make it easier to use, they hid/removed the features I used, such as “how much is in my account right now?” or “pay a bill”. That stuff is now hidden in a complex menu system. I can manage the MasterCard I don’t have though.
Designing good UI is an incredible skill, one that few people gave, and one even fewer are willing to pay for.