Pittsburgh was abandoned as a hub by US Airways starting around 2004. Twenty years ago they flew to about 120 destinations from Pittsburgh. By the end of the decade they had only half that number of flights and were using just 10 gates.
The airport has attracted new service from low cost carriers, but is no longer a hub. They haven’t had service to London since US Airways eliminated Gatwick service in 2004. Today the only transatlantic flying from Pittsburgh is seasonal Frankfurt service (Condor), seasonal Paris service (Delta) and year-round Reykjavík flights (Wow Air).