Eh, that's only a four decker. I question the math. We already have a two decker for ~ 101.6 K...would 1 million not require a ....what...20 decker?
It may be that as you go up in layers you can move the upper decks out a bit, but it sure doesn't look that way in the pic.
And I don't even want to think about the traffic
Having said that, here is a fun mental exercise. There are over 5 million people in the state of Tennessee. 1% of 5 million is 50000. Thus on a game day with a sold out stadium, about 2% or 1 in 50 people in the state of Tennessee are in Neyland. Mind blown!
Of course, there are out of state Vol fans and visitors, so maybe it's more like 1.5% or whatever, but still! 1 in 75 people in the entire state in that small of a volume is pretty amazing.