What I did find interesting in the articles is the report that AA has already started cancelling several of it's 777 flights beginning in February? They report they are doing so based on expected pilot retirements. Are there no pilots who can move up to keep these flights on the schedule?
Moving up requires training and scheduling that training requires time. It's not a one day process. They've to to fit in the training while keeping the other flights in the air. Usually, a very well coordinated ballet, but things fall apart if more retire than anticipated. That's the major inefficiency of having multiple fleet types that airlines like WN avoid.
The larger than expected pilot retirements may be related to the recent boom in the Dow, as AA pilots, IIRC, have a several month look-back period in determining the lump-sum value they can withdraw at their retirement. Same thing happened in 2000, when late that year more pilots retired than anticipated because their lump-sum distribution was calculated on the early 2000 stock market peak instead of the much reduced value later in the year. Same thing also happened at Delta that year.
Another factor might be a "four in ten" kind of rule (if that applies to the pilots), by which their pension is calculated based on the best several years out of the past 10 years of earnings.