This answer is for a previous version of the question
The most persuasive answer to this that I have read recently can be found in "American Nations: A History of the Eleven Rival Regional Cultures of North America" by Colin Woodard. It has been a few years since I read it, but if I remember correctly, he posits that different cultural patterns that were set in the first few generations of settlement got propagated and reinforced, so that even newcomers to specific areas acclimated themselves to the unique regional culture.
In the case of the South, it took two wrenching national interventions (the Civil War and the Civil Rights Movement) to get their racial assumptions to move as far as they did. Other Southern characteristics that were not specifically targeted against have carried on unimpeded (honor culture, Protestant Christianity).
I do think that your question as currently worded carries some implied bias in that the North should not be portrayed as more "noble". There was plenty of racism throughout the North too, in both the nineteenth and twentieth centuries. Abraham Lincoln had to walk a very fine line to not get ahead of northern pubic opinion about black people, and later, plenty of northern unions worked to keep blacks out of good positions.
Admittedly, this a hard subject to discuss without bias. I could relate anecdotes from work talking with people throughout the country, and I can certainly see a different style of work and set of values between a New Yorker, a Southerner, and a Upper Midwesterner. These general impressions are real but hard to quantify. What unit of measure does one use to say that a New Yorker values speed and competitiveness, Southerner values personal relationships, and a Midwesterner values honesty. How do you discuss the negative traits without being offensive? How to you calculate an average of a region given the person-by-person variation?
Hypotheses regarding climate causing different traits in the population have been around at least since Montesquieu, but they often run into a problem of proving causality instead of just correlation. Like any social science, you do not have the luxury of setting up experiments with proper controls solve questions about human behavior.
Regarding your supposition that certain types of people gravitated to "like-minded" areas, this does not seem to borne out by history. Most immigrants in the period 1820-1920 moved to the North and West because that was where labor was in demand and better remunerated, due to industrialization. The labor shortage was less in the South, enabling institutions like sharecropping. It is possible that the "Northern work ethic" could be related to the fact that getting better rewarded for work makes one work more, whereas poor rewards teach a more lackadaisical attitude.
Most of these observations cannot be "proven", but they do provide fodder for discussions of what America is and can be. They also show that there is not consensus on what America "should" be.