The problem with Apple making only one of them is that they can only have one priority list, while the myriad of Android devs can have as many as users do. iPhone's list is something like:

1. Web Browsing 2. Music/video 3. Games 4. Email/sms 5. Phone

That's almost the exact opposite of every corporate user, and most teenagers.

It will be interesting to see if they ever release a second model, the way they eventually put out different lines of iPods. Maybe something bigger and less flashy, but with a keypad and way better voice. I won't hold my breath, but it might work.