iPhone 1/2/3/4 are evolutionary devices, better hardware of same kind, same software, same software ecosystem. PS1/2/3 are different hardware architectures, different software and different software ecosystems.
Can you run the latest OS on an iPhone 1? Can you run the original OS on an iPhone 4?
I can see how they're not as different as PS 1/2/3 but they're definitely not the same device. Steve Jobs would slap anyone who dared say that iPhone1 and iPhone4 were "hardware upgrades with same software and software ecosystem"
You can't run the latest OS on an iPhone 1 because that would hurt Apple sales so they won't let you. There's no fundamental technological reason for why this can't be done. Same for the other way around. iPhone of all generations share the exact same hardware architecture, they are no more different than a PC with i7 and a PC with Core2Duo.
Different generations of consoles are completely different hardware architectures completely incompatible.
I can see how they're not as different as PS 1/2/3 but they're definitely not the same device. Steve Jobs would slap anyone who dared say that iPhone1 and iPhone4 were "hardware upgrades with same software and software ecosystem"