Really? Everywhere I look, I see screens of up to 4.5" max. Only about 30% of phone users around me have bigger screens and of those who do, 50% say they would have preferred smaller but did not get the choice.

In other words, only about 15% of the population wants huge screens. There is a LOT of market for smaller sizes. The way I see it, the manufacturers force the bigger sizes on us for the same reason applications and OSes eat more and more resources: laziness to optimize.