Males are less expensive than females--you can purchase a morph male for perhaps $75 these days. In a pet store, normal balls cost $60 or even more in some cases.

One male can fertilize up to 3 females in his first year of breeding, and even more as he reaches his full size. Males breed around age 1. Females need 3 years to grow to adult size.

Because of all these factors, adult females are quite valuable. You can place one morph male with a half a dozen normal females, and get around 18 morphs in your clutches. So, the perception is that placing a normal male with morph females would be a huge waste--you could have gotten a morph male for very little more money, and gotten back a huge return on the investment, as opposed to the much smaller return from using a normal male. It seems a waste of potential income to use a normal male with a morph female. She can only be paired once each year. The male can be paired with many females.