they would have done better with just a gigantic poster of ferris bueller in a towel.

You are a marketing genius!

But also, I think it's just a trend in the U.S. For a while there, and kinda still, warehouse stores are in style; I think because of the reputation for good deals from places like Costco and Ikea, I think other companies thought if they pretend to be a bit of a warehouse people will think they're getting low prices because money was saved on decor. 'Muricans are easy to fool this way.