Your unfamiliarity with the facts of what happened is noted. "Delta" was unable to acquire the additional aircraft, according to management. As there were no other E170's on the market, obviously, there were no more to acquire for CPZ to fly.

Regarding S5, they were fortunate to be able to place the Frontier E170's back into the DL system. S5 was going to get the flying anyway as they already had the aircraft. Nothing was awarded to them that CPZ or anyone else was supposed to have done.