Longevity does not come close to telling the whole story. Gojets has 10 days off, 1-2 weeks of vacation max, 1% 401K match, no min day, no cancellation pay, 70 hour reserve guarantee, I would guess their health care is not stellar, 50% deadhead pay, etc
9E has 11 days off min, up to 4 weeks of vacation, 50% match up to 10% (5 times Gojets), min day, cancellation pay, leg by leg guarantee, junior man refusal, 200% pay junior man, reasonable health care, short term and long term disability, 75 hour reserve guarantee (that's about $435 more per month than Gojets min), 75% deadhead pay, etc.
That's just off the top of my head.
So if you were Delta, even after this TA passes, and GoJets can still do it cheaper, wouldn't you just wind down 9E and transfer the flying to GoJet?