First of all we need to clear up some facts. A company's first obligation toward its shareholders is to make money. Being number 1 in terms of unit sales doesn't necessarily apply to making the most money.
Sometimes the costs releated to grabbing a larger market share are higher than the the extra money you make. Xbox vs GameCube is probably the best example of that, where Xbox was bleeding money during its whole life cycle, while GameCube actually was in the black quite early in its life cycle and stayed their for most of its life.
In some ways the same can be argued with Nintendo 64 vs PlayStation, where Nintendo 64 in terms of unit sales was 1/3 of PlayStation, but still managed to make money almost equal to Sony's monster success.
What does this have to do with being first to market? Well, considering the prime objective of a new hardware release is to make money (both longterm and short term), the timing of the release is mainly based on the need to overlap the end of its predecessor. In other words;
1. Dreamcast was released early because Saturn was dying, and Sega needed new cash flow.
2. Xbox 360 was released early because Xbox was dying.
3. Wii U was released first of this generation because the Wii was dying.
etc.
In other words, selling most units isn't as relevant as people seem to think. Most essential is to make as much money as possible on every single unit sold.
