That was a bogus theory started by Gruber
back in January 2012.
Not only does it make zero sense (if you want to conserve battery, you use a smaller screen like Apple does), but his predictions based on such a flawed premise turned out to be incredibly wrong:
"If Im right, we will start seeing smaller LTE Android handset sets a year or so from now, and the tech press will collectively forget the bigger is inherently better mindset that pervades phone reviews today. - Gruber"
Uh, no. Not even close. Instead, even Apple joined in with the bigger display crowd.
How come no android maker has put a flagship phone is a small package? I believe it was because they could not get the design to fit in the small spacing the way Apple could. By giving themselves more volume to work with, they could do a lot of things that they had to do. They had to include a bigger battery because even with the bigger battery their battery life was terrible. They had to overclock their CPU to get rid of the lag. Remember the GS3? You were lucky if that phone made it from the morning until 5 p.m. Samsung couldn't make that phone thin and with a small screen.
But, yes Gruber and others did not realize that many people want as big a screen as possible while still being able to fit in a pocket. Many of my friends have the 6+ and swear by the larger screen now. But I think the android guys ended up there partly by happy accident. Nokia also made large screens and big phones and I'm pretty sure it is because they couldn't make the phone small. Blackberry's Z30 has a large screen. It is also heavy and thick. They want to make a thin phone, but they couldn't. Now the top android guys can make their phones thin. But it wasn't the case three years ago when they started the Phablet move.
----------
There still is a population os 4s, 5 and 5c/5s that would be ripe for the 6s or 7. But generally I think you are correct, about the universe of those who will upgrade.
I'd guess that by the time the 6s comes out, 70% of iPhone users will not be using a 6. Also 100% of non-iPhone users will not be using a 6 (and that will be the vast majority of cellphone users). So there is still going to be a huge universe of potential customers to sell the 6s to. We have no idea how good a phone it will be. We can guess that its form factor will be the same, but we don't know how it will compare to its competitors. But judging by past years it will arguably be the best smartphone money can buy when it comes out.
And we do know that the story of iPhone saturation has not played out in any way shape or form so far. And we've been hearing this story and the "law of large numbers" year after year now.
So there is a huge universe of potential customers and a strong track record of producing one of the best products in the industry. We could be looking at growth again next year.
