I hate to be a downer but any number of things can happen that could set the industry back years. In no important order or likelihood:

More mainline mergers, overall reduction in mainline capacity (happening already), terrorist attack, oil spikes higher than it is, multi pilot license, regional liquidates, scope loss (either willingly or by bankruptcy), cabotage, JV's and code shares at the majors, and years down the road - drones and possibly single pilot operations (unlikely but still possible in 10-20 years)