Of course there is a market and readership for long form essays and reporting. The problem is they "monetize" poorly or at best monetize as well as the "here are the 20 hottest cosplayers at PAX Prime". As the editor you can spend a lot of man hours over a long time producing one piece or spend a weekend taking pictures and dumping the images into the "gallery component".
As for why Polygon doesn't work, I'm not sure it works or fails but simply exists. Someone can claim that "1 for 3" ratio but I wouldn't know it. The only people I see re-tweeting Polygon links are Polygon staff. The only time Polygon articles get cited here is when they have a serious controversy which isn't exactly the most positive light. Are these articles really that good? If so then Polygon needs some serious PR help because no one but Polygon and GAF knows it.