A lot of commercial kits are based on military kits. There is an obvious difference between being in a military situation where you don't want to be found necessarily (and hence might be 'surviving' for a long time) and a 'civilian' situation where you are desperate to be rescued a.s.a.p. Personally, I carry fishing kit in my 'wild' PSK, but not in my 'urban' PSK. I carry one or the other dependant on what I'm up to.