May have something to do with the fractional ownership of the commuter/regional carrier. I believe Delta does not have any fractional ownership in SkyWest - but
as regards Compass or Endeavor there may be such an interest.
Count your blessings if you can travel S3B - No matter how many years of seniority you have the new hire with one day on the job trumps that which makes you feel real good !
Such is the way the Delta travel benefits are ! Remember that at one time or another when you were active/working you trumped retired seniority and offline carriers!