He wasn't talking about id in that last sentence. Rage has a deep lure that id has developed/written. Deep in this context just means vast and detailed.
A 20 hour game is deep? Stalker will give you hundreds and Fallout is ridiculously detailed with lore covering hundreds of years.
Vast and detailed, well we'll see but I very much doubt there will be even a small fraction of either of the games I've mentioned.
I have 411 hours in Fallout New Vegas. 300 in Stalker on Steam and about the same outside of Steam so 600 hours for Stalker. About 300 in Fallout 3, a bit of a guess here.
I have 17 hours in Metro 2033 for two playthroughs. I imagine Rage will be a bit bigger and longer. Deep and vast ... LOL.
I have and have played all id's games, well not all of Commander Keen.