While it's difficult to find county-level internal migration data from before 1990, it's possible that a lot of Steelers fans ended up in North and South Carolina due to African-American reverse migration to the South. Many Northern cities have seen this in the past decade.
Deadspin is speculating. I don't think the guess is correct. But I could be wrong. In fact, I wish I knew more about Pittsburgh's African-American Diaspora. The national trend is well-documented. (As the links in the quoted passage attest.) This recent return migration is long (decades) after Pittsburgh's root shock exodus.
Via Chris Briem (Null Space), a wonderful piece of sports journalism about the Hockey Mom Diaspora in the "South" that didn't sit well with me:
Within the decade after the first Saturn rolled off the assembly line the NHL started looking for cities in which to put their expansion franchises. Nashville badly wanted one. The NHL granted a group of businessmen in Nashville a franchise on the stipulation that they sell 12,000 season tickets by a certain date.
"The owners who took a risk, starting a hockey league in the middle of the South in an area where people hadn't grown up with the game, they knew what they were doing when they came here," Herron explains. "They knew there were so many people moving to the area from Pittsburgh, Michigan, Chicago, all of these hockey towns. They reached out here first."
Both the Saturn Corporation and Local 1853 agreed to promote season-ticket sales among the plant workforce and in the community. They had no problem hitting their mark. In 1998 the Nashville Predators debuted on the ice.3
For years the team's fans called themselves "Preda-Wings" — they were Predators fans until the Red Wings came to town. But the popularity of the sport and the Predators has grown beyond the enclave of Midwestern transplants. "Now it's catching on," says Herron. "People like the game. You go to Predator games now and they throw the catfish on the ice." The catfish thing is an homage to the Detroit tradition of throwing a dead octopus on the ice.4 "When I first saw that I thought, That is just sweet! That is the Southern version!"
"When the Predators came to town, all my kids wanted to do was play hockey," says John Feeney, president of GNASH. "I was always a football guy growing up. My kids were never interested in football. It wasn't fast enough. It wasn't challenging enough. Just a lot of standing around."
Emphasis added. The Saturn automotive plant was near Nashville, in Spring Hill. You might think locals were thrilled, with the prospect of jobs. You'd be wrong:
"A lot of people in Columbia were anti-GM," one former GM transplant tells me. "They thought they should have got those jobs." The Nissan plant in nearby Smyrna opened years before with a mostly local workforce, so naturally the residents of Columbia and Spring Hill thought that Saturn would do the same thing. That's not how it worked in General Motors, though. Union members had the right to the jobs first, and there was no shortage of members in the Midwest who wanted to work for this "different kind of car company."
The "South" was overrun with blue collar Yankees. The problem is, Tennessee ain't a part of the South. It's the heartland of Greater Appalachia. Stories about the Great Migration usually discuss the relocation of African-Americans from the rural South to the urban North. Forgotten is the Hillbilly Highway:
Briars, first off, are what (some) Ohioans call workers transplanted from Appalachia. In the mid-twentieth century, Dayton was the port of entry for many Appalachians migrating from KY, TN, and VA looking for jobs as the coal mines were dwindling. After World War II, when factories such as General Motors were heavily recruiting, 7 million migrated north. The whites tended to settle in Ohio and Pittsburgh, while the blacks tended to settle in Detroit and Baltimore.
White Appalachians also settled in Chicago and Detroit in large numbers. There were discernible ghettos in those cities. Detroit's Little Appalachia still exists.
Another round of root shock has the Briars in a great reverse migration of their own. I figure more than a few of them ended up in Tennessee, where right to work didn't exactly mean no union in the auto plants. The Scots-Irish are back where they started.