The article mentions that change in perception of costs in childhood vs adulthood, but there is another possible psychological (or sociological) factor: desir

The article mentions that change in perception of costs in childhood vs adulthood, but there is another possible psychological (or sociological) factor: desire for increasingly complex (== more blocks) Lego sets among customers. This is similar (obv. not identical) to the digital authoring tools available to everyone today were only available to sophisticated content creators in the past. Of course the digital tools I have seen a massive deflation in unit costs. What would confirm this hypothesis is a graph showing the distribution of sets sold by # blocks per set, over a long period of time.