That's the best-case scenario. Another scenario is that you don't have perfect memory and don't always recall where all 80 (5 screens of 16) of your apps live, so you go to the right looking for an app, and you don't find it, so you then have to go to the left, for a total of 6 swipes. I'd bet that this is a pretty common scenario for most people with enough apps to fill 5 screens.
1) I organize my Android's 3 screens by function: (left) Scheduling/Tasks, Home, (right) Social stuff. On each screen are a relevant widget (or two) and related apps.
2) The Android app drawer is much more useful than iOS's app pages because the app drawer is arranged alphabetically, is continuous and is organized top-to-bottom. I use the drawer about 10% of the time and, when I do, I don't need to "recall where all 80 apps live" because I recall the alphabet.
... a total of 6 swipes. I'd bet that this is a
pretty common scenario for most people with enough
apps to fill 5 screens.
But then the question of 4 swipes vs 2 is kind of moot. You're not using 5 screens to store apps, so comparing your setup to iOS isn't apples to apples.
Personally, I setup my 3 screens (iOS) to have 1. Stuff I use a lot, 2. Stuff I use a little, 3. Stuff I barely use. This works well for me, and going to a left-center-right model wouldn't gain me anything (I expect that it would cost me instead).
> 2) The Android app drawer is much more useful than iOS's app pages because the app drawer is arranged alphabetically, is continuous and is organized top-to-bottom. I use the drawer about 10% of the time and, when I do, I don't need to "recall where all 80 apps live" because I recall the alphabet.
This is debatable. There's something to be said for not forcing alphabetical order. It comes down to personal preference, though.
In popular launchers (including the 'stock' one) there's the "app drawer", accessible from all home screens. It's an alphabetical listing of all installed apps; it is ~5 icons wide and scrolls vertically.
Icons (shortcuts) or widgets added to home screens are merely user-created convenience shortcuts to get to apps.
This is analogous to desktop shortcuts vs navigating the start menu on Windows.
edit: commandar replied with a similar sentiment while I was writing this.
(I think you may not have realised commandar's and cristoph's replies were not written by the one person)
Certainly, offering the option to put apps on the left of "screen 1" is not a problem if that's what you prefer. I'd probably never use that if I were on Android, though. Of course, Apple already uses "screen 0", so the "swipe left" option is already taken by search.
Your point only applies if you fill the 5 pages with apps as they're installed, iPhone style.
As I've said a number of times, the usage patterns are too different. If you're using your screens as folders, then maybe you want the left-swipe functionality. If your screens contain every app you install, then that might not make so much sense.
I'm not saying Android is wrong to have left/right screens, merely that the behavior would generally be wrong for iOS.
I still use the App Drawer (the alphabetical list of all installed apps) occasionally for the rare app I don't use frequently to merit a prime spot on my home screens.
If it's not something I use all the time, it can live in the app drawer rather than be in my way on a home screen.
As for accessing things quickly, an iOS user can stick all their "social" apps in a folder on their main screen. The 5 screens can easily become a single screen, with 1 click to open any folder. Left and right swiping don't even mean anything here.
As I said, it's not Apples to Apples. Saying that iOS should have left/right screens because it works on Android doesn't make sense if the usage patterns are different.