People in the mid range and low end do, as do OEM's, power consumption is very important them since they can cut down on component costs on desktops thus dropping entire system costs.That pricing would be disastrous. Next-generation, same performance, exact same price. Oh, and it runs cooler and is more power-efficient-- but who really gives a crap about that on the desktop?
A very low-power GPU with 390x-level performance would be interesting for laptops, but that assumes GP106 doesn't compete in that space. Nah. Prices have to come down.