You do come off as a bit pretentious and condescending there. Saying that anyone who didn't predict solo Charizard is incompetent does imply that sort of attitude.
Now, I do think you make some good points. However, I still believe that there was reason to think that the Pokemon Trainer would return. Let me try explaining this from a different perspective.
Now, as you've made quite clear, Charizard is the most popular and most promoted starter of the original three. The Origins special and the two mega evolutions prove that, naturally. However, I believe it's worth mentioning that Charizard has always been in that position. He's always been the most popular of the three, and has always received bits of special treatment from Game Freak because of this, even before X and Y introduced Mega Evolutions and all that. The reason I bring this up is because I've noticed you haven't really addressed one thing in particular; why was the Trainer added into Brawl in the first place? Why was such a difficult to develop character even considered for the roster, and why did such a concept even make it into the final product? Given Charizard's status as the most popular Pokemon of all time, him getting in solo then wouldn't be much stranger than it would have been now; if any of the three starters got in alone, it would have been Charizard. Despite that, the Trainer, along with Squirtle, Ivysaur, and Charizard, made it into the roster together. Notably, Charizard was the starter to get in fully evolved, which reflected his status as the favorite of fans and Game Freak, while the others got their earlier evolutionary stages. After all that, then came along X and Y, where Charizard got quite a bit of goodies just for him, like the two Mega Evolutions and being the starter of choice of the Origins special. However, the other starters, and their evolutionary families, weren't exactly left behind to rot. It wasn't like with the Hoenn starters where Blaziken was put in the spotlight and the other two were completely left out of the picture. The Squirtle and Bulbasaur families were both available in X and Y as well, and both those families received mega evolutions as well (naturally, it wasn't Squirtle and Ivysaur who got mega evolutions, but the attention given to their families is still present). To a good number of people, what was going on with the starters in X and Y was just a continuation of what we've been seeing for so long; the original starters being treated well while Charizard, the fan favorite, gets special treatment. This is how it's always been, and how it was in Brawl as well; Charizard was the one who was playable in its fully evolved stage while the other two starters got lesser forms. From that perspective, there wasn't much reason for the Trainer as a whole to be cut aside from developmental issues, which didn't keep him out of Brawl, even though it very well could have.
That's how I viewed the situation prior to the Direct. Go ahead and say that I'm using fallacious reasoning that's too ambiguous and isn't actual evidence, I guess. I just feel that there was reason to think that the Pokemon Trainer could have returned, and that you shouldn't declare all of us who thought he would return to be incompetent and illogical in hindsight.