They don't have the "wish". It's just the result of evolution. If life didn't survive then it wouldn't exist. It exists simply
because it survives. That doesn't mean there is a "wish" to survive. It is simply a trait that it had. Then evolution kicks in, and any life that doesn't survive when environments change dies off. So you're left with "life" that appears to "want" to survive. And then life mutates, and mutations give rise to an improved survival rate, not because of any "wish" but simply because those that didn't have those mutations died out when the environment changed (and I don't just mean the climate, but resource environment as well, etc).
Imagine you have a load of rocks of many different sizes.
You put them through a large-holed sieve and discard those that don't fall through. The ones that fall through "survive".
Then you change the environment and now you have a sieve with smaller holes. Those that now fall through "survive".
You repeat this until you only get very small rocks, everything else being discarded along the way.
Do these small rocks "wish" to survive the process? No. It is just a process. And the rocks either survive or don't.
But the rocks at the end, if they could, might look back at the process and go "wow... we
survived through time. We must
want to survive. We must have a
wish to survive."
But they don't. They simply survived the process.
I hope that helps explain my view?