Most of the people who do get killed by them are unlucky (spider falls onto you from the shed roof, the snake you surprise has just finished moulting, can't see you properly and is scared and angry so strikes just in case, or the scorpion or centipede decides your bed is a wonderful place to sleep just before you get in). And of course there are the others who are careless or think it could never happen to them, like the ones who get taken by a croc right under the 'No Swimming - Crocodiles' sign, or ditto for sharks or stinger jellyfish, or the ones who step over a log or put their hand into a dark hole without looking, or tease a snake or a funnelweb until it bites them, or forget to shake out their boots before putting them on..... Some people are really silly like that.
The few times I've been bitten by venomous spiders, one fell on me from the shed roof, one was in the collar of a shirt I put on straight from the clothesline, one was in the middle of a plant I was picking in the dark. The first couldn't be helped, the second and third I might have avoided with more care. Snakes: one bit me when I was climbing, reached up to a ledge above my head to pull myself up, and failed to perceive the snake which was sunbathing there. The other was crazy-aggressive and actually attacked me, but only grazed me before I managed to kill it. I hate killing snakes, but in that case I hadn't much choice. But that's two out of thousands of snakes I've seen, and gods know how many I've passed and didn't see.