What are the odds Republic can ditch all their present contracts (read: source of funds to continue in business) and set up a new airline using very expensive C-Series? Very nearly zero! Every scope clause in the US prohibits a regional carrier from operating a RJ with greater than 76 seats or 86,000 pounds.
If they could sell their C-Series positions to generate cash, don't you think they would have done so OR BBD would have made the sale?
It ain't over, til it's over, but the possibilities have to be within reality.