Complex sentence: The PSA route network slowly disintegrated within USAir and was gone by 1994: most of the former airline's assets were scrapped or moved to USAir's hubs on the East Coast.
Split into simpler sentences: The PSA route network slowly disintegrated within USAir and was gone by 1994. Most of the former airline's assets were either scrapped or moved to USAir's hubs on the East Coast.