"The P3 turbo prop configuration is the most efficient airframe for the mission."
It was good in its day, to be sure. But the high-bypass turbofans on the MMA match or better its loiter time. They also, due to their increased speed and lowered maintinence requirements, completely change the way you do business. With newer buoys and analysis systems now in the works, it's no longer required to spend all that time down low.
As well, the MMA eliminates about two crew members (the FE's), and its increased loadout of buoys and fuel means you can do a LOT more. Oh, it also has true inflight-refueling capability.
As I said in a previous post, it is thought that one MMA can replace three P-3's.
No doubt the MMA is a better all around aircraft for the job, but what's the happy medium? If the money's not there, and the program is to be cancelled, I'd rather see you flying in safe new proven airframes of old design, rather than bandaided up 25 year old ones. The Russians aren't making anymore superquiet subs, and the P3 avionic package is perfectly suited to track what's out there. The Chinese are years away from having the capability of the former Soviet Navy.
DATs are becoming obsolete. DLTs are the favored format for large tape volumes.