> They're almost ridiculously diverse, and the prompts show very little handholding was required.

The structure is identically to all of that, big title, graphic, list with icons. As said, they look fine on their own, the problem is only becomes apparent when you had to look had hundreds or thousands of them. It's the em-dash or the "load-bearing" of the AI-art world, the more you look at this stuff, the more apparent the similarities become.

> Hollywood movie posters and book cover designers are notorious for reusing the same tropes and colour systems, and that's been true for years, long before AI was a thing.

Exactly, but with AI that issue becomes even more drastic since the models don't create diversity by default.

> Most artists aren't diverse either

They don't have to be, since there are millions of them, all coming from different backgrounds, with different art styles and all. While there are only a handful of big AI models, who all come with a pretty generic default style.