I'm no expert on anything, having given that disclaimer here's my useless opinion!
I can understand wanting to make fire and shelter quickly if you've just fallen into water.
Lets say your canoe turns over then along with your wet clothes you'll have to swim to shore with a pound of metal hanging from your belt. I don't know how practical that is?
Also would having a long knife on your belt be particularly comfortable sitting in a canoe? (I suppose it depends what type of sheath you have).
But you should stop if you're lost and make fire and shelter way before hypothermia sets in. To keep pushing and wait for the first signs of it then try doing something "fast" is a bit silly.
Every time I go out I'd much rather have a survival bag on me than a chopper of any kind. But then I don't live in the wilderness so my experience would be totally different to yours.
I know most people use the falling in water and getting wet thing as the main survival situation, but getting lost is what will happen more often than not. I mean MOST people go boating in the summer when it's warmer and less of a threat of freezing to death, and if something happens, it is USUALLY during day light hours anyway, and not midnight......unless you're a drug runner or something.
Even if you are out on the water, you should have some sort of PFD on. Wearing one would off set the one or two pounds of knife you might be wearing plus the 25 pounds of wet clothes that you are now sporting.
If you aren't wearing a PDF, then I think the 3 minutes without air will do you in before the cold water and lack of shelter will 3 hours later, but what the hell do I know.
I also agree with you on the stopping and building shelter before your bad situation turns into a survival situation. You're right, it is silly that people don't stop sooner. I'm not sure why people keep walking and walking when lost, but they do. I am also not sure why people wait until Dec 24th to do all their Christmas shopping, but they do and they keep doing it EVERYTIME. Go figure.
I mean why put yourself into a Christmas shopping survival mode with a bunch a crazy, stressed out, pissed off people? I have almost ALL of my shopping done right now for Christmas. Plan ahead is all I can say.
I don't want to get this thread off track, so I will answer the main question as to how much. I am going to answer it as SURVIVAL and not wilderness knife.
For me, a wilderness knife is something that you have as a back up to a larger knife. Something you have with you around camp. I wouldn't carry one while hiking myself. It just can't do some of the things I would want it to do if I was to end up in a survival situation.
Again as I have said before, I am planning on doing everything in the dark, because that is human nature to get HOME and not stay out all night unplanned.
I am not going to be making nice piles of fire wood. I will chop big chunks of wood, because in the dark, that's probably all I will be able to find for both fire and shelter. I will chop them into the smallest pieces I can lug around in the dark and maybe that means wood that's 6'' to 12'' in diameter and 5' to 10' long. I'm not cutting or breaking them into normal fire wood length. I will just burn the wood and keep pushing it into a fire. No magic and nothing high speed low drag.
I will do some cutting of branches to try and make a shelter. Maybe cut some twine as well. And maybe think about cutting my throat for being so dumb to wait until it zero dark thirty to be building fire and shelter, and wonder what they will find first, my body or their Christmas presents I have already bought and hid for them.
Batoning, maybe a little, but not the first night. I have learned a couple things when I was younger. When I finally accept the fact I'm lost, I have learned to start gathering tinder and small sticks while I am walking during the day light, and pocket them. I will also find a longer straight pole and use it for a walking stick and a support for my shelter if it comes to that. Once I have these few things in my grubby hands during day light hours, fire and shelter building is a little easier.
That's about all I really see happening with a knife in a short term survival situation.