Steel is too heavy. As they pointed out aluminum is much better at dissipating heat than titanium. Shooting video has always heated phones up. A lot of the video features were aimed directly at actual professional video work so I’m not surprised if preventing throttling was a key goal. Game performance will come along for the ride as well.

They also said that this was the first unibody iPhone. Can titanium be made the same way? The unibody MacBooks are really nice though I’m not sure if the same rigidity issues are at play in such small devices.