Not all women want a huge dick stretching them out. My Wife certainly doesn't.
Also, as women age, many of them begin to lose the elasticity in their vaginal tissue, which causes intercourse to become uncomfortable and even painful. This will also lessen their ability to accommodate a large dick. There are creams that can help, but must be prescribed by a doctor and applied regularly, which can become expensive.
So, some of us will just have to learn to deal with the fact that our wives may never wish to experience sex with other, largely hung men.