I don't see anything particularly outrageous there, 40 - 80 AMPS, @ IP65 or better, that can survive in the field is always going to cost (The Lemo stuff makes these seem cheap, but the Lemos are really, really nice).
Have a look at the Souriau UTS series for some cheaper parts that may or may not suit, also Harting have a massive range of sometimes interesting connectors.
Generally, MIL anything is a cost multiplier, but there are intermatable plastic mousing versions of those circular bayonet connectors that are cheaper.
For low current controls stuff, there is a semi standardized 4 pin affair that is used on industrial control valves and some servo motors, cannot remember the name, but it will be easy enough to track down.
FWIW, when pricing connectors of this sort, Farnell/Mouser/Digikey almost always quote daft money, talk to a specialist supplier for far more reasonable prices.
Also, something to watch, many connectors are only IP rated when mated, and they sometimes leak like a sieve when unmated, just a subtle gotcha that burned me in a salt water environment.
And yea, connectors costing more then the electronics is fairly routine.
Regards, Dan.