I agree, there's definitely more percentages to gain and possibly even new fab techniques that can result in more densely packed chips using less power. Howeve

I agree, there's definitely more percentages to gain and possibly even new fab techniques that can result in more densely packed chips using less power. However, those will (likely) be exploitable regardless of when the fab was built. The limiting factor isn't likely going to be the fab equipment so much as the techniques used. That's where I don't know that bigger better fabs is going to be the arms race that it has traditionally been.