The senior guys (enough of them anyway) presumably had the ulterior motive of helping the company avoid BK, or possibly even liquidation. Or at least helping it hold it's market position and not be crippled by cascading waves of training events over several years, while single-fleet LCC's eat their lunch in the recovery.
Unlike most of the union labor examples you mentioned, pilots are locked into their respective companies by the seniority system... their wagons are chained to one pony. Apples to Oranges.