I think if you look at the aluminum and RTV molds available, most are patterned from (or exact copies of), the most popular baits out there.
While it is good to create new baits like Big Z and Bob, Del and certainly Machinist has, most anglers want tried and true designs so those are the molds that many hand pour/injection companies want.
As long as there is no patent infringement, each manufacturer and individual should, and can, make whatever molds they deem the market desires.
Jim