eli5: If we have methods like desalination, why is the world suffering from a water shortage, when 70% of the Earth is water?

Question

Even though the water is saline, to the best of my understanding, you can convert saltwater into freshwater so why is there a water crisis?

In: Biology

Answer 1

Because they can be costy.

Although there is a way that you can desaline water by using sunlight (which I suppose is *kinda free*)to evaporate the water, you might need either a lot of time or a wide area to produce considerable ammount of fresh water for public consumption, maybe both.