Interesting point about how there's no reason why book covers couldn't be as plain as in the old days.

Persephone seems to share your view. It publishes books in different versions: the "plain" versions (which I showed in the image that appears with the story) and livelier ones. I love that approach.

That approach acknowledges that some people prefer plain versions and may find even find splashier cover images distracting. But the livelier ones can attract different readers who'd appreciate a book just as much. Here's the splashy Miss Pettigrew that attracted me:

https://persephonebooks.co.uk/products/miss-pettigrew-lives-for-a-day-classic