Never underestimate the power of a brand:

Analysis of the world’s top brands shows Lego has replaced Ferrari as the most powerful

On familiarity and loyalty — I suppose it helps to get them (b)locked in at an early age:

Lego is the World’s most powerful brand. It scores highly on a wide variety of measures on Brand Finance’s Brand Strength Index such as familiarity, loyalty, promotion, staff satisfaction and corporate reputation.

(via Brickset)