Even if every mainline flight out of Pittsburgh canceled (all 22 of them) it wouldn't cause too much of a ripple. Customers would just be reaccomodated on Express flights which vastly outnumber mainline flights, and operate most of the flights to other hubs/focus cities for rebooked connections. Even if all the Express flights canceled as well for lack of ground handling, the amount of flights is so small it wouldn't be any major catastrophe as there are very few connections through there, and none that can't be handled through either of the two hubs.
As for the commuting issue what does that have to do with the holiday? The base closes in January. Even then, all that is happening is throwing 300 more people into the mix. Assuming variables such as number of flights and open seats remain the same, the same amount of people get to work as would have were there no upcoming base closure. The same accountabilty for being in base exists that everyone else is held to, and has been. One can choose to go by car, train, or bus, or go a few days early. Not getting to work only results in putting one's own job in jeopardy, and justifies Philly's reserves who are traditionally underutilized in January.
The company is NOT on your side as far as commuting. They do not care if we get to work. In fact, they would prefer that we don't make it to work to a point that our employment is terminated either by them or by us. They'd be thrilled to replace all of us with lower paid, less drama new hires who can pour a Coke and close a door as well as any of us for a third of the cost.
I commuted from a notoriously tough place to commute from... it sucked, made me hate the job I normally love, but it was the smartest choice for me financially at the time. Commuting is an entirely different lifestyle, and it's a lonely, costly, risky and time-consuming one. If I could offer any advice, know all of your options, including multiple stop Zed fares on other carriers, and ground transportation. Start early. Befriend other commuters, and befriend locals in your new base. Do not expect any sympathy from the company, even though they put us in positions where we feel we have no choice (I was once in three bases in under a year), ultimately, it is a choice.
That's just reality.