I think its easy to confuse "strength" with "size", that scrawny guy could be very strong or very weak. Ultimately we are talking about moving heavy things on our backs over varied terrain. Heavy is relative, could just be you and your gear, meat excluded. Neither strength nor stamina is the absolute best, but rather a ratio that works best for you. An example that helped put things in perspective for me had to do with 2 guys, 1 very strong not much if any cardio and the other not very strong but excellent cardio. The goal was to get a refrigerator up 20 flights of stairs. who wins? The stronger you are the easier it is to move a load. I don't think of strength as how much you can curl or bench press, but rather how heavy a pack you can safely take from the ground to standing and loaded on your back.
Very good point. And it's not inconsistent to be very strong and run a 5 minute mile. It's not an "either/or" question. Better to have a mix of both.