The difficulty of the problem. Small accidents. (Say the way control keys work differently from MacOS than most OS.). Trying to satisfy the expectations of many different users. Getting high in their own supply. No real competition. People get used to it. The corruption that comes with advertising. Management and developers with fixed ideas. Fanboys. Systems that don’t work for users can be more profitable than those that do work (see match.com). Failing to capture small opportunities because they aren’t large enough. Internal conflicts in organizations.
These connect: “getting high on your own supply” is connected with “advertising” and “fanboys”.
Your options as a consumer are
https://en.wikipedia.org/wiki/Exit,_Voice,_and_Loyalty
and “exit”. Loyalty in the other hand is bad for you. I remember when Google came up with the thoroughly boring (competent and refined today if still flawed) Material Design and there were people who wanted to tattoo it on themselves or make their whole house up in Material Design. You hear from some macers that they would rather put their hand in a toilet than use Windows but the same folks seem to be spending most of their time at the Genius Bar.
Reward success. I pay for Jetbrains IDEs because they are a refined product and I am not the product.