Why can’t my iPhone do this? Apple has horizontal modes in some (but annoyingly not all) core apps, so why can’t they add it to the home screen as well? It wouldn’t necessarily have to be just like my mockup, which fits an additional 4 apps and drops the text labels (could get them to fit nicely), instead each individual icon could just swivel 90 degree left or right so they are the right way up when you’re looking at them. In horizontal mode you might also flick through your various home screens by scrolling up and down instead of left and right.
iPhone horizontal home screen
Why can’t my iPhone do this? Apple has has horizontal modes in some (but annoyingly not all) core apps, so why can’t they add it to the home screen as well?

I was thinking about this too! It is akward when using it horizontally for it to always be a verticle homescreen. Also I thnk that all or most apps should be able to work horizontally as well, it’s easier to type and there’s wider viewing area. Maybe in iPhone 4g?
It must be really easy for apple to change that but what would be the point of having horizontal home screen in a first place? In my opinion, up and down scrolling is a bad idea as right and left swipe is more intuitive (especially in horizontal layout) At the end of the day, iPhone is still just a phone so why complicating things?
But then again, everyone has their own likes and wants, so maybe they could add this option in settings area with an on&off switch so everyone could decide if they like it or not :-)
I asked my friend the exact same question last week. Lying in bed reading emails and then exiting to go to another app is awkward when everything is vertical on the home screens.
Nice mock up there, I agree it would be so easy for apple to do too, and the icons swiveling 90 degrees would be awsome.