Four four years now, the iPhone has been by our sides enslaved to our every whim and demand. But the iPhone we’re used to today is not the same iPhone of yesteryear. Want to know what’s changed? Read on.

So lets go over what has changed If its in bold its Camera. If its in Italic its Audio Output

What has changed camera wise.

The iPhone Original and 3G ended up having a built-in Fixed focus 2.0 megapixel camera located on the back for still photos. It has no optical zoom, flash or autofocus, and does not support video recording, however jailbreaking allows users to do so. Version 2.0 of iPhone OS introduced the capability to show location in the pictures.

The iPhone 3Gs upgraded to a 3.2 megapixel camera, by OmniVision, with autofocus, auto white balance, and auto macro. It is also capable of capturing 640×480 (VGA resolution) video.

Now the “BIG” upgrade: The iPhone 4 upgraded to a 5.0 megapixel camera , also located on the back, which is equipped with a backside illuminated sensor capable of capturing pictures in low-light conditions, as a LED light capable of staying lit for video recording at 720p resolution.The iPhone 4 has a second camera on the front capable of VGA photos and SD video recording.

Has Audio Output changed at all?

The bottom of the iPhone sports a speaker and a microphone  flanking the dock connector. One loudspeaker is located above the screen as an earpiece, and another is located on the left side of the bottom of the phone.

The 3.5 mm TRRS connector for the headphones is located on the top left corner of the device.

While the iPhone is compatible with normal headphones, Apple provides a headset with additional functionality. A button near the microphone can be used to play or pause music, skip tracks, and answer or end phone calls without touching the iPhone.

Between the Original, 3G, and 3Gs nothing has changed until the iPhone 4

So, Should Apple have just made 2 models, because to me nothing has really changed