I've got an iPhone XR with a chunky (highly protective) Speck Presidio case that's comfortably thicker than the camera protrusion and therefore lays 100% flat.

Gotta say it would drive me nuts to have a phone that didn't lay flat and couldn't therefore be put down safely on the edge of the sink etc.

It is really freaking obnoxious, I can attest to that. I think they either don't want to be mistaken for a Pixel for vanity reasons, or it's easier to do the magic camera switching if the 3 cameras are closer together. But for whatever reason, I hate not having the cameras in a row with a plateau that is symmetrical.