>Rural areas with almost zero industry are averaging out at 600-750K.

Where exactly? Not true for the midwest. E.g. (1,2,3)

1. https://www.zillow.com/homedetails/933-Atmore-Ct-Indianapoli...

2. https://www.zillow.com/homedetails/10916-S-Wabash-Ave-Chicag...

3. https://www.zillow.com/homedetails/3920-15th-Ave-S-Minneapol...

Here's what you might find 20 miles outside boston, this one is 350k:

https://www.zillow.com/homedetails/55-Emory-St-Brockton-MA-0...