Why cant more gyms have swimming pools

I traveled to premier fitness today after work to see what their gym was like and I was impressed to the point when I asked them if they have a swimming pool and they said no. Swimming pools are such a necessity for gyms and every gym should have one if its big enough. It has to be one of the big factors that affect customer's  discisions to sign up for that gym. So really all im left with is the gym thats the most pain to get to that has a swimming pool. I had a year membership for it before and it was good but I was also living walking distance near it at the time.