But is the diversity really that staggering?
I mean most animals including possibly dinosaurs that have ever existed share a lot of internal organs, in the same place. They have eyes, brain (with a lot of the same brain areas, even birds have something like a prefrontal cortex but it's called something different).
They all have legs, torso, head.
I would say there is a lot more commonality than difference. The differences come from slight variations on a basic template that works, and then the body looks different and so on.
I'm not sure how to think about the diversity that evolution creates and how diverse it actually is. I would say there are _a lot_ of repeating patterns all across history, with variations on those repeating patterns always changing.