I think most people (not including myself or some of you), no longer demand big performance increases in their Macs because you can do so much in a web browser and on the iPhone. And even if they want better performance every year, battery and cooling capacities are becoming the more significant limiting factor. Battery tech just can't keep up.
Gimmicks like the Touchbar are Apple's attempt to increase the Mac's value proposition. It's kinda like 3D touch on the iPhone -- who really needs it?