Sorry Nokia devices are comparable in dimensions to iPhones, they haven't been double the thickness today or in the past. There is definitely a noticeable difference between a mono speaker and stereo speakers on a small device. Maybe try covering your ear and tape it up for a whole day and see what a difference a lack of sound balance makes on your experience. On small devices sound is directed outwards and then reflects back off other surfaces then to be received back by the ear. Lots of people use their devices without headphones with the device oriented horizontal using the built in speaker. Watching videos with friends, listening to music or other recordings by themselves, playing games isn't uncommon. Stereo speakers improve the experience dramatically especially when playing games. Maybe you will only accept stereo speakers are essential once the overdue idea is neatly packaged up as a marketing talking point in a future Apple keynote for you to indulge on. This is the problem though, not enough people evaluate things critically. For the amount of money iPhone uses pay they aren't getting great design.
Stereo speakers on a 2009 Nokia are just as bad an idea as they are on a 2016 Nokia. The same is true for the iPhone of any generation. What was a bad idea in 2009 is a much worse idea in 2016 now that devices are considerably thinner. The speakers are too small and poor quality to offer any kind of enjoyable listening experience, stereo or otherwise.
If Apple does introduce stereo speakers on the iPhone 7, at the expense of the 3.5mm jack, and tries to spin this in a marketing talking point, I'll be the first in line to accuse them of the very same thing you accuse them of in your earlier comments:
"Protruding cameras and obvious antenna lines are what define Android devices and Apple lowered its standards by adopting Android device standards." -- smacrumon
Except, I'll add "stereo speakers" to that list of stupid design decisions most commonly found on Android and Nokia devices.
If you can explain why the iPod is the most popular portable media players in the world, yet never had built-in speakers of any kind, much less stereo speakers; and there have further been 6 generations of the iPod Touch, one of the most successful portable media players and gaming platforms in the world, and has never had stereo speakers, then maybe we'll have something more to discuss. In 16 years, Apple has never felt the need to add speakers, or later stereo speakers to the iPod line, and yet it's been one of the most successful products of its type. I don't recall customers clamoring that stereo speakers were "essential" to the device. Indeed Apple didn't think so, and this is during the period where you claim in your earlier comments that Apple knew what it was doing.
It's clear to me, Apple knows stereo speakers on such a small device are anything but "essential", and offer at best a poor quality user experience. Apple knows adding a second speaker is a marketing gimmick used by inferior android, and Nokia products in their attempts to compete with Apple on something other than quality, offering their customers novelty over the best experience. And Apple's customers seem to agree.
If stereo speakers on such a small portable device were "essential" as you claim, then Apple would either have them after 16 years of making iPods, and almost a decade of making iPhones, or everyone in the world would be using Androids or Nokias (and last time I checked, Nokia did so poorly selling phones with "essential" stereo speakers they had to sell their phone division off to Microsoft, who is still doing so poorly with the brand, they have to give the phones away).