Oh please... Reducing the side bezels would save something like 1/6 of an inch on the width?
Assuming the rumors are true, Apple determined that 4.7" is the best compromise (for them) between size, portability and energy use/cost while still being noticeably larger than the current 4" iPhone screen.
It's pretty ridiculous that some people here are trying to make us believe that adding 1/6" on the sides makes a big difference. And palm detection is still an imperfect technology, a minimum of bezel is a good thing for usability while making a negligible difference in width. How much bigger could they make the screen by removing 1/6" anyway? Would that really make a big difference? I don't think so.
Some people seem to want bezel-less designs because it looks futuristic more than anything.
As for the top and bottom bezels, they have little impact on usability as smartphones are mostly held by their sides. They enable Apple to put a better camera without adding a "bump". And seriously, the additional space they take in a pocket is not a big hassle like some try to make of it. They add what, one inch?
The difference between the iPhone 5S and the Galaxy S5 is huge. But even if the S5 will still have the biggest screen, the difference between the iPhone 6 screen and the S5 will be considerably reduced vs. the 5S in the eyes of a lot of people despite what's being posted in this forum.
Edit: And BTW, the Galaxy S5 side bezels are pretty large too, I don't see anyone complaining that they "wasted" that space when they could've put an even larger screen without increasing the width.