Intel 3770K CPU with HD 4000 GPU can hardly handle World of Warcraft on 1920x1200 resolution screen with 25fps on lowest settings at a place what deserted and made 5 years ago. We talk about a desktop CPU what is more powerful than mobile versions. And to be honest we know WOW isn't that demanding game. Just imagine what fps can we get if we use it on 2560x1800.
OK, now tell us how many MacBook Pro users play World of Warcraft. Darn few, I'd venture.
You don't seem to understand - people who buy Macs are generally not looking for the latest, greatest gaming experience.
So, in the end, you don't really have anything to back up your claims.
The HD4000, while a "big step up", is still a fair bit less than twice as fast as the HD3000 in real world tests. If we're being generous we can go with Intel's 2x benchmarks. Fine. The Retina display doubles the pixel dimensions of the screen, quadrupling the number of pixel. So that's half the graphics power per pixel of the previous generation laptop. I think that's fair to call not cutting ice.
IOW, you don't have any evidence to back up your claim.