Mechanism
Apical Meristem Growth
TL;DR
Amazon's sequential category expansion exemplifies apical meristem strategy - concentrated growth at specific tips.
Trees grow at the tips. Period. The technical term is "meristem" - specialized tissue at the ends of branches and roots where cell division actively occurs. The trunk doesn't grow thicker through cell division at its base. The branches don't expand along their length. Growth happens exclusively at apical meristems (shoot tips) and root tips.
Business Application of Apical Meristem Growth
Amazon's sequential category expansion exemplifies apical meristem strategy - concentrated growth at specific tips. Master one category (books), then leverage competency to adjacent categories. Each new category is a growth plate where resources flow and intensive development occurs.