It was founded when waterways were the main transportation access point, and boomed as it was the intersection of 3 rivers. But today Pittsburgh has an airport that isn't a major airline hub, with limited flights that need a connection from most cities. Rail by Amtrak is infrequent and impractically slow. The drive from NYC is 6 hours, 5 even just from Philly. And extremely treacherous in winter, too - winding Appalachian mountain passes with icy roads, blizzards, fog, narrow lanes. The nearest neighboring city is Cleveland, which isn't exactly a big boost economically.
Contrast to Philly on the other end of the state and you're 2 hours from NYC, Jersey, DC with high speed rail, a major intl airport etc. Sure there are west coast cities with worse problems, but they still have the optimism of manifest destiny working in their favor. Getting caught in a blizzard driving to Denver just feels more exciting than a blizzard driving to Pittsburgh..
If Pittsburgh doubled down on the airport or got cash from harrisburg to improve rail links to NYC (we can dream), maybe build up as a tourist destination even, it could be competitive. Till then, yinzers are going to have to enjoy the secrets of their charming city on their own.