It's Right sizing so they can drive away people who want real F and mainline to other airlines such as AA/DL. Then, there will be lower demand for paid F, they can change the flights to EMB145/CRJ200/Q400 to do further right sizing. It is what the new company looking for. MCI has similar situation. There were 757s, A320 and A319 with CRJ700s before.
Now they cut the 757, reduce the frequency of A320/A319 and replace most CRJ700 to EMB 145/Q400. It's right sizing so people can choose AA or DL without a second thought. DL put more mainlines to MCI and it's the company to make money .......