Blame me... and most buyers as well.
Why are they making large screen phones? Because people are buying them up as fast as they can make them for the most part. Back when the SIII and Note 2 came out... people initially scoffed and made fun of the size. That is, until people bought them and realized that, gee, you could SEE! And around this time, faster more powerful networks began to spread. Watching higher definition video was now possible since you can both see and stream the content.
I mean, can anyone sit there with a straight face and say that they prefer to watch a video on an iPhone 5S over something like a Nexus 5 or Note 3? Because that's what phones have become... they've become mobile entertainment centers. And who hooks up their Bluray player to a 20 inch TV hung on their wall?
Yes, the smaller iPhone 5s is less bulky and if someone has small hands, it is easier to deal with, but people, even those with small hands gladly sacrificed a little bit of comfort for the return of getting a large screen.... The whole "people with small hands don't want big phones" is bunk... I mean, I see plenty of teenage girls around town rocking Notes.
over the past few years, EVERYTHING has gotten more complex; people are demanding that their cameras, which most now sport double-digit megapixel counts, show detail and they'll want to see that detail. Mobile games are no longer just graphically simple affairs like Angry Birds or Doodlejump... many of the top sellers are HD immersive 3D games that we used to only see on desktops and consoles.
Don't fret though, the leaks of the new Moto X show a device that really isn't that much bigger than the current model. Samsung just released a 4.7' screened phone.... Sony has an excellent unit and LG has one ready to come to market as well... not to mention the upcoming iPhone 6. There will be plenty of options in that size range.
Me? I say deal with it... I got big hands and a new G3.... as Goldilocks would say, it's just right.