I'm not and expert on survival scenarios or training, but I do posses a somewhat unique perspective on this issue because I've volunteered in a mounted SAR unit for almost 14 years. So I've seen people who've been stuck in "survival situations", from forest fires to lost climbers.
In that time I've seen people do very well and others do quite poorly when dealing with whatever sort of trouble they ran into. I won't say good gear doesn't make a difference, it does, but I can't remember single one of these people being saved by a super bomb proof knife.
An old guide that had an accident on the mountain (broken leg) while gathering mushrooms and herbs managed to stay alive with just the thin kitchen knife he used to collect the plants. He was close to a village when we found him, he was in good spirits and offered to brew us a cup of tea. In a few more hours he would have reached the village by himself.
On the other hand, we had plenty of people with super high end gear end up endangering themselves. I remember to rock climbers we found who were very well equipped but panicked and didn't even think to take advantage of their gear. They weren't idiots, I talked to them at the hospital while they were being checked and rehydrated. In fact, we found them because they left a game plan at the tourism office.
Anyway, what I mean is that any decent knife is good enough if it's backed by knowledge and a cool head. Different designs need different techniques, and some people will always prefer one style over others. I like knives with 4" or 5" blades that aren't too thick and have learned their strengths and weaknesses. A mate of mine, being the rain forest savage that he is, does everything with a machete (and I mean everything, the guy can mow his lawn with a machete and do it perfectly). We give each other a hard time, but we both get things done.