Lyxen
Great Old One
I find that without individual xp as an incentive some players tend to always have their characters - no matter what class or type the character may be - hang back and leave the risk-taking to others. And if nobody takes the risk the game/story stops in its tracks; somebody's gotta do it, and that somebody should be rewarded for it.
First, have you considered that it's a characteristic of your gaming group, having been trained in survival by the type of adventure that you run ? We never have that kind of problem at our tables (we have different ones, for sure, but not that one).
Second, again, rewards don't have to be in terms of XPs. It can be in renown, respect from NPCs, connections, or even monetary or magic for the risk taker, for example.
That said, if survival is the primary goal of the PCs at all times the presence/removal of xp shouldn't make any difference in how the party as a whole approach things. If when you removed xp you also removed lethality that'd be different, but the two are unrelated things.
That's a bit of the problem, if your world is so deadly that it prevents risk-taking, you have the real source of the difficulty, and dangling XP carrots does not look like a reasonable solution, better to stay at home than adventure in these cases...