They want to get Helium 3 from the moon, and several asteroids are known to have rare earth metals, in some cases to a level greater than found on earth. There is a lot of real world practical uses for mining everything out in space. We need those resources and it is a given that we will be mining them in the future. Right now it costs a lot of money to get stuff into space and that is the only reason we are not already doing it. Looking for life is a side project to the mining of valuable resources though, don't underestimate the value of that is floating around in space.

I said in a life time because I think we will be in space within my life time. I think in the next 20 years we will have some form permanent base in space, and I am extremely confident that we will within 50 years. Then again, we might not actually need humans to do this stuff. Robots might be able to do all the work for us in space. So we might have a robot base in space without people living there. I think people will want to go there though.