“...Buffalo straddles...”
I agree with your analysis. Buffalo is where my husband’s clan originated and we love the down to earth people there when we go to reunions; there is most definitely a more mid western attitude and mid western feel in Buffalo then can be found in the snobbier east coast New England states.
I grew up in the southern tier and a logical case could be made that the mid western mindset might begin even farther east than Buffalo; the “pop” vs. “soda” terminology for soft drinks could even be the demarcation line. I think that cuts through the state around Syracuse.
Pop vs Soda IS a shibboleth. It IS pop, of course.