In 2009 I had extensive conversations with the design team. The scale device is a critical feature for people who want to use the maps app as a map. Google's response to it's removal then was they expected people only use the maps app as a "background upon to place directions." That's why they only display major street names, only display ranges in the context of directions and keep removing the scale device.

It's not a map application, it's a wayfinder.