Business analysts have long recognized the cyclical nature of the retail industry, but you don’t need an MBA to notice the seismic shifts happening in retail today. New industries and products are being born, as once-thriving businesses fade. In every case, changing behavior is behind these industry trends, and in most cases, new technology is driving these changes. Tablets, smart phones and similar devices have made life increasingly portable and, arguably, more efficient. That’s good for us, but not so good for many established businesses. Below are five business models that are going through tough times — and the future doesn’t hold much promise, either.