There's no major international air hub (anymore) and flights even to nearby cities such as NY, DC, and Philly are relatively pricey with limited schedules. There's no meaningful international service either anymore. This is in comparison to SFO, which has direct international service to many cities in Asia and Europe and fancy flat-bed planes (on the hour) to NYC... Austin has direct service to London and Frankfurt and flights every 30 minutes to mega hubs in Dallas and Houston, and well, New York is New York.
Even by car, the closest nearest city at a two hours without traffic is ... Cleveland, and while Philly, DC, and NYC are drivable, you're looking at 4-5 hours without traffic to Philly or DC and 6-7 hours to NYC if you're lucky. And it's not the easiest of drives either with the winding and truck-filled PA Turnpike.
Even within the metro area, there isn't much outside the downtown core. A few nice suburbs to the north, south, and east, but there isn't anything to the scale of the Bay Area, even with it's housing crunch, nor the Pacific Northwest, nor even Austin / San-Antonio.
In short, it's hard to get to and out of, and while there's an exciting transformation going on, at the end of the day unless someone revives PIT as a major transit hub, it's still going to be a relatively isolated post-industrial mid-western rust-belt city.