Interesting thread. However with no real conclusions
I cannot speak for the airline pilot but from a bush flying instructor point of veiw I think its safe to state the obvious that so long as the "Airline Pilot" is also current in genuine hands on bush flying in light aircraft between his airline flying then he may be able to handle a "bush flying" situation as well as or better than the full time "Bush Pilot".
Real Bush Flying is mostly about flying small airplanes with decent STOL capabilities in remote and challenging areas of the bush. Not airliners!
Cheers
CC