I was interested in getting into the kit business, before I wised up, and one thing a very successful manufacturer told me was this: You can make all the Kawanishi flying boats and Supermarine Spitefuls you want, but you had BETTER make a CUB and a MUSTANG if you want to even THINK about surviving!
All the jet manufacturers make all the same planes because they are what SELLS. There will always be fifty F-15's bought for every F7U Cutlass.