They have been produced, but x86's dominance has always been about fungibility and idiot-proofness while maintaining acceptable performance. It's never been the fastest possible or cheapest possible architecture; it's the architecture whose success has been built upon hiding all the complicated bits behind the curtains, so that software people can worry about software and not hardware.

There actually are some performance upsides to that too. It allows the chip architects to radically change the underpinnings of the chip with impunity, doing whatever works best on the current process node and using the latest advancements from computing research.