It's obviously not for the money!
We do it because we have passion and curiosity that far exceeds a desire for life stability. We teeter on the edge of poverty for a profit of knowledge we use to push the boundaries to make some sort of difference it what we know as "existence". Although it would be nice to not have to worry about if I am going to be able to afford groceries each month, I wouldn't want to do anything else.
I am a biologist and my life is crap!