Designers alone can't push through a change for the sake of change as their work relies entirely on user research. Even if they do have the research needed to prove a change is required, they also have to get developers on board.
So I don't know where this conspiracy theory comes from, but it's entirely unfounded unless you're talking about a designer like Jony Ive with the power to go through multiple obstacles with ease, in which case the change isn't happening to prove he's needed but because he has a different vision.
It's the case everywhere. A designer (in the context of software/hardware) does not work without user research, that is core to their work. Any position that does not require user research in design is titled differently these days.
So I don't know where this conspiracy theory comes from, but it's entirely unfounded unless you're talking about a designer like Jony Ive with the power to go through multiple obstacles with ease, in which case the change isn't happening to prove he's needed but because he has a different vision.