But it's not down to polygons or details in the environment - the simple architecture still looks realistic with the addition of realistic lighting. In the quest for realism, modern games have so many details, dirt and grit everywhere [1]. Perhaps going forward artists can let the lighting do more work and still represent realistic clean environments. I loved this blocky room in Half Life 1 for the dramatic (prebaked) lighting: http://combineoverwiki.net/images/thumb/3/37/C2a4e_lobby.jpg...

[1] just look at Doom 2016: https://cdn.arstechnica.net/wp-content/uploads/2016/05/20160...