Flowers usually contain more stamen than pistols why do you think this

Pollen, like sperm, must be made in large quantities. Much of it is lost and very few actually reach the stigma to fertilize the ovules. Having more stamen insures there's more pollen, so there will be a higher chance of the pistil being fertilized.  Flowers often contain a single pistil, but may contain  several. Staminate or "male" flowers contain only stamens and lack pistils entirely.