Revealed preferences assumes that there are no confounding factors, no tyranny of small decisions, no information asymmetry and an unlimited selection of products that vary along every combination of features. It’s economic drivel, and serves only to dismiss opinions out of hand.
Then that's an entirely different point. There are many reasons why small phones don't sell well. There's the changing market in which a phone is the primary computer for many people. There's incomplete information, as the tethers in a showroom prevent you from holding a phone one-handed, or noticing that it is too big to fit in your pocket. There's a potential for decreased design costs, as a larger space provides more options for how the phone's internals can be arranged.
But calling those "revealed preferences" is a sleight-of-hand. It takes all those external factors and treats them as something intrinsic about the buyer, to be "revealed" by the market. The term itself is a lie.