Both AS and B6 are in deep trouble going forward, although AS could always shrink back to a small regional carrier. B6 has already sought and been largely denied an exemption from the route / frequency requirements of its CARES Act bailout and that does not bode well.
Going forward, it will be the large corporate contracts which dominate as the recovery progresses. Neither B6 nor AS can break into that because they lack a (significant) international network. How long one or the other has been around is irrelevant.
The bottom line is that B6 is doing itself immeasurable harm by its fraudulent handling of refunds. US law is clear on this point and a passenger who requests a refund is due one. Entirely fair to offer a premium for a voucher/credit, but telling a passenger who is legally entitled to a refund that he may not have one is something that many people will not soon forgive. Especially those who do not read up on DOT Warning Letters, accepted a credit and find out later that had they pushed B6, they could have had a credit.