They all look the same because they're all generated by the same service. LLMs used for GenAI are mediocrity machines regardless of the medium.

And companies don't try to visually distinguish themselves from one another when using AI because the entire point of using AI is to try as little as possible so as to get a product to market as fast as possible. And who exactly would be doing the trying anyway, the designers and artists that the company fired and replaced with a prompt engineer (who is probably using AI to generate their prompts?) There is no longer a human qualified to make such decisions anywhere in the loop.

This is the way the future of design looks now, best to get used to it.

often, you have to have a really compelling reason to change a widely adopted user experience, people get used to expecting things in certain places and operating in certain ways

I don't see a ton of design space here. A bunch of them wanted to change how developers work with Ai (cursor/antigravity), but I just use a CLI in a VS Code tab/pane along with the files. VS Code is quite flexible and you can customize your layout (I swap left/right drawers, people comment on it occasionally)