Primitive tech or not, it looks to be a useful explanation, especially if as you say ground truth and mindshare say something different from the typical commercial map. Is your worry that Google would prefer folks not use their data as a basemap? Look up "open street map" for a much more freely useable dataset.

Since you note the interstate corridors as main boundaries, I wonder if the "wrong but typical" definitions just predate the interstates. Bring in the bulldozers on that scale, and start limiting traffic across the expressways, and you definitely bust up old patterns.