Running some quick upgrade numbers for those interested. 2 scenarios.

Scentric 1. We lose 300 captains to the flow next year and hire 300 FOs to replace.
Most junior upgrade awarded was an October 2010 hire.
300 after that pilot is a November 2011 hire. So upgrade would stay the same through end of 2017 at 6 years.
300 after that though started class on monday. So 2018 upgrades would be around 2 years.

Scenario 2. We lose 400 to flow and are able replace them with new FOs.
Same pilot is most junior captain awarded
400 after that pilot is a march 2014 hire. Meaning upgrade would drop by end of 2017 to 2 and 3/4 years and would continue to fall as there aren't even 300 pilots following that pilot.

Rough numbers based on an old seniority list but illustrates how quickly upgrades could drop here and current times don't necessarily project future upgrade times.