Some of the R1 memories are maybe a little lacking in relevance to the modern MPA (it wasn't even an MPA for a start). These days it doesn't take 30 people to operate, and the entire interior of the jet to fit in, steam powered sensor systems.
The MRA4 had already shrunk the crew requirement from 13 to 10 and I think the P-8 has a crew of 8.
The MPA task may not need to be fullfiled by a single type any more. Some countries have already chosen a mix of manned and unmanned aircraft.