This seems to imply that when supply changes, demand also changes. This is untrue. However, you could also be implying (partially correctly) that in the near future, both preferences will change, resulting in lower demand (correct), and supply will increase (which is technically untrue, the quantity supplied will increase, but the ways to acquire the items will stay the same). The quantity supplied increase, which will cause a shift along the demand curve, not a shift of the demand curve. However, I do believe that the demand curve will shift because of a change in tastes and preferences of consumers. So, you're right but for the wrong reasons.