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.
This is true in the Scranton/Wilkes-Barre metro's tax base collapsed more quickly due to the Knox Mine disaster exposing the cracks in the anthracite mining industry. It is also true that Reagan doing very little in terms of federal subsidization to stop the hemorrhaging of the ironworks industry as well as refusing to protect manufacturers from foreign competition undercutting the market left a very bad taste in the mouth of a lot in the Steel Belt. However, it was
not a smooth transition into a service economy in any sense. The promises of economic revitalization from the advent of I-81 and the Northeast Extension never materialized because logistical support+retail inherently creates less economic value than the design, manufacturing, or extraction of raw materials. The Scranton of the late 20th century was the poster child for industrial decay; everyone who could leave did. To this day are almost as many over 65 than there are children in Lackawanna/Luzerne. "Who has it worse" now is suburban Pittsburgh by a fair (though not wide) margin; who had it worse in the 80s is like choosing between gonorrhea and dysentery.
The reason why NEPA was more conservative than the southern counties Pittsburgh metro during the heyday of the New Deal Coalition is the latter being much more heavily unionized. Very long history of organization, strikes (Homestead, Johnstown in 1937, 1952 nationwide). Class consciousness was prevalent in NEPA, though the large Catholic population ultimately was a larger determinant of voter behavior. This is why it flipped in 1928 in opposition to Hoover's term, not 1932 with the New Deal realignment. After all, Luzerne was a state bellwether at all levels until 2018 and Lackawanna went for Ike in '56 while Stevenson was victorious only in the 4 counties in the southwestern corner of the state plus Philly.
Tl;dr: Lackawanna went for Ronnie because while the NE coal region was left-leaning, labor didn't quite have the same clout as it did in West Virginia/the Pittsburgh metro. Despite what everyone Atlas seems to believe Appalachia is no monolith.
