The 1990's were fifteen years ago. Since then Carmack has spent 60 hours per week writing code for every conceivable console, PC, and mobile platform. Most people in his position would have moved into management by this point, he chose not to. As a result he has more expertise on more topics than just about anyone else in the gaming industry. And more than most in computer science generally. If he has an opinion on something, its because he knows what he's talking about.
I'm not saying he doesn't know what he's talking about, he just never liked consoles, he was always a PC guy and if he were truly "excited" about the nextgen that's like hearing Armstrong will quit riding bikes and be a F1 pilot.
And I'm saying, your opinion is stuck in the 1990's. John Carmack was very excited about both the xbox 360 and the Nintendo Wii. He's just not excited about the next generation because, in comparison to the most recent generation, he believes we're at diminishing returns for having more and more powerful 3d graphics. Which is exactly why he's taking VR headset development into his own hands.
