@GreenWings
Big UAV cannot do everything a Nimrod can. Nimrod cannot do everything a Eurohawk can. (e.g. hanging out 24 hrs, 5 hours out at 60.000 ft)
As I wrote, you probably need combined types. The time s societies were so uninformed and scared they were willing to put aside tens of billions to pay for home developed solutions for everything is gone.
Trying to put everything thinkable in 1 250.000lbs, Ex00.000.000, 10 crew, fifties airframe for 1 nation proved so out of touch it's hard to believe IMO. The lobby to get the plan approved must have been overwhelming.
E.g. Tanker/ Transports could do surveillance and SAR roles if necessary. An ASW platform too could be much smaller these days.
I think it will go that way. We see developments in the carrier, transport, AWACS areas already.