People who got the 4, enjoyed the retina screen for a full year before the 3GS owners got a sniff of it. The 4 owners also got a 5MP camera that for the first time could substitute for a point and shoot.
While the original 3GS owners who skipped the 4 and were upgrading to the 4S, the 4 owners upgraded to the 5 and have been utilizing the benefits of a 4" screen for almost 9 months now while the 4Sers are still stuck on a 3.5" screen. The 5 owners also had LTE all this time to go along with a beast of a processor.
Now while the 4Sers upgrade to 5S this year, this current 5 owners will move on to an even bigger phone when the 6 launches next year, while the 5S owners show off their scuff free phone and dual LED flash and 'refined' design.
This isn't rocket science. I don't see how you don't get the fact that the non-S folks get the best upgrades and upgrades that actually matter first. If people are so worried about design issues on a new generation phones they should not preorder at launch and should just wait a month or two to let Apple iron out the problems.