I'm not sure why nobody is talking about the elephant in the room: Bootlegs.
I don't support or condone it but its effects are really easily seen in emerging economies (like mine in Malaysia). We had a very quick boom in 2014-2015, fueled by the Poly pack Shell lego craze and the scarcity of Modular sets, causing rises at even 30% above RRP.
Suddenly in late 2015 came the onslaught of reasonable quality bootlegs from China, and it steered much sales from those willing to buy genuine at RRP (but no supply). Note that the 30%-50% premiums above RRP for big sets are a significant proportion of our average incomes. By the time Lego stabilized the supply with their new manufacturing facilities, we start to see even larger and more expensive sets (so called Ultimates etc) which I can understand from a business perspective of trying to upsell, but at the same time I feel that many of those willing to buy big sets were already sated by then.
I have no solution towards piracy, when you can see that in emerging economies is rampant in entertainment, creative products and even in cars nowadays. But it is certainly a factor against growth and demand for Lego.