Essentially, it breaks down to this.
- Is more expensive
- Is heavier
- Takes too much energy to produce
- Transmits less light causing shorter battery life
- Is too difficult and expensive to machine
- Is difficult to get in large quantities
Even objections that look like constants can be misleading. Take the properties of sapphire. Presumably, when Gorilla Glass was first introduced, Corning received similar attacks: glass is brittle, glass will break. But they faced the criticism head on, took a scientific approach, and created a much stronger product than many believed was possible. Even constants might not be that constant.
- Too expensive
- No keyboard: doesn't appeal to business customers
- We're selling millions of phones. Apple isn't selling any yet.
- Short driving range
- Take too long to charge