>>35531570But they DO promote those 3 every time. They all get reasonable and equal promotion unless one of them turns out to be a breakout star. In terms of merchandise, Greninja had virtually the same amount as the other two for its 1st year even despite being exponentially more popular than the other two. It was until the 2nd year that they started to capitalize on the hype train big time, once the fanbase had been set. Same goes for Charizard.
The Pokemon Trainer argument is futile too, because we didn't get the 3 final stages: we got the most popular of each respective stage, with Ivysaur as a third wheel. The stage choice is also meticulously laid out to appease to as many as possible, but not under the naive assumption EVERYONE will be pleased. Hell, even today i know of people that would've preferred it to be Bulbasaur - Charmeleon - Blastoise, but that would be a horrible idea marketing-wise.
Even now, you DO see equal representation in starter shilling, albeit it is done in the Most popular of each line to avoid overlap. Hence why you see a bunch of Chespin merch, Braixen merch and Greninja merch.