phonescoop.com

speedywalk said:
...That being said, I know the lack-luster black slab of a phone being touted today doesn't make for a great logo either. Kinda' reminiscent of "what's that rectangle in their logo for?"...

...and that's the answer.

Today's phones don't have any recognizable shape suitable for an icon/logo.

We prefer the old design (with a keypad and antenna stub, at least) because it's instantly recognizable as a cell phone.

For the same reason, nearly all phone interfaces use an icon of a landline phone handset to represent the phone app and send/end actions. It's recognizable as a phone. A rectangle isn't.

We may remove the pull-out, whip-style antenna from the logo before long, but it will still look like a phone from ten years ago, and we're fine with that, because at least it looks like a phone.