I think the "no more coupons or discounts" played a huge part in this failure. This whole strategy was something brought in by ex-Apple Retail Store exec "Ron Johnson" when he became CEO in 2011.

My own speculation is that he tried to apply hard-line strategies that work when you have a unique good with strictly-set pricing (Apple products), but fall apart when you're selling goods that people can get anywhere for a variety of prices (e.g. Levi's jeans).