I believe that the mining and industrial areas of NEPA (Lackawanna, Luzerne) began their decline and transition into post-industrial-ism somewhat earlier and more smoothly than the analogous downwardly-mobile coal and steel areas of the southwest that were Fritz's core in the state, and thus had somewhat more of a modern middle-class that was more amenable to Reagan. These people existed in the Pittsburgh metro too, of course, hence why Allegheny County voted more republican than further-flung Beaver, Fayette, etc., but were outvoted by industrial areas whose decline was then less dire than today, more than the remaining industrial centers of Lackawanna could outvote the more affluent parts of Scranton and its immediate environs.
I don't know enough to say if Pittsburgh encroachment partially replacing the fleeing industrial base played a part in turning counties like Beaver or Washington red in the 21st century compared to the presence of that contingent in Lackawanna, but it's something that I should look into; just a quick look at Census data shows some Beaver municipalities growing slightly between 1990 and 2000, possibly indicating some truth to this conjecture.
Admittedly I'm not an expert on this part of the world, and this is a fair bit of speculation.
I think your analysis makes a lot of sense. It’s amazing how at the county level PA looks so radically different in 84 with the exception of Philadelphia and Pittsburgh proper.
I did a medium dive into Beaver County a while back when my curiosity was peaked by an old blog from 2008 which identified it as one of the few non-rural Kerry-McCain counties. One thing I found interesting is that even today Aliquippa went for Biden by a fairy comfortable margin despite being almost as white as the surrounding small towns, even in 2016 there was virtually no swing towards Trump. Sort of similar to Greenfield, MA and (though I’m not sure if it holds as much demographically) Waterbury, Connecticut. It seems like there’s a pattern of impoverished Post-industrial cities regardless of exact demographics remaining heavily Democrat.
This is not entirely true. Aliquippa 7 & 8 - the most white precincts in the city - were won by Obama by 24 and 30 points respectively in 2012 and then ended up being narrow wins for Clinton and Biden. Its Democratic strength is largely because the black parts of the city held up better.
