It is not a myth, and I have observed this over multiple years.
I lived in the Midwest and Lived in California.
The neglect by coastal cities and DC exhibited by both DNC and GOP from the 1980's onwards allowed what you are calling the Gingrich doctrine to "happen".
When a party abandons (and this is a form a severe abuse btw), an entire area "and" then states we are just waiting for you to die off?
What does that say?
Obama comes into power on the backs of liberal and moderate republicans, and what was given in return?
Health Care Tax and severe shaming.
Bill O'Reilly states it best:
The Democrats and the liberals within are sadly good at tolerating intolerance tolerantly.
Compassion and Empathy left the red and rural lands long ago, and when these areas voted for a cult of personality who was a democrat before he went to the GOP.
There was no acceptance and the actions were not liberal. In fact they are the dire opposite of liberal.
Ironically, cities like NYC and San Francisco may get a taste of the Midwest Blight due to COVID.
A canary in a coal mine? The Coca Cola sign that has been in San Francisco since 1937 is getting pulled down and taken away.