The airline filed bankruptcy soon after Northwest did and things have been getting uglier ever since that time. They were in an epic struggle with all their labor groups to reduce costs and they were unable to come to an agreement. Because of that, they would not have been able to offer Northwest a competitive bid for flying the small planes, and the airline would likely have just been liquidated.
Mesaba received permission to impose their own contract terms through the bankruptcy court (like major airline partner, like son), and then earlier this month, the labor groups were forbidden from seeking self-help of their own. Apparently, that was the impetus for the labor groups to settle, because the pilots and flight attendants settled in the last few days and the mechanics, the last holdouts, settled today.
To be fair, these are tentative agreements and so the membership still has to approve them, but this has been a long ugly road and I hope the saga ends soon.