True or not, this is something thats always worried me about graphics getting better. I remember playing a game, cant remember which, but i walked intoa room that was lavishly detailed, with detailed assets and texturs, of which was only in this one room in the whole game, and it was a room you just walked through ina few seconds. And i was thinking 'how long, and how many, devs did it take to make this one room, and you just walk through it'.
I think doing open world games will bypass that a bit as you can ust fill the world with assets and textures you made. Linear games must surely be either going shorter, or away completely, just because of the money price involved.