Apple's iPhone: The most profitable product in history | Business Analysis & Features | News | The Independent
"To date, Apple has sold more than 750 million iPhones with a margin of nearly 70 percent. It's the main reason Apple is sitting on a cash pile of more than $200 billion. The iPhone represents 60 percent of Apple's revenue and has driven it to become the world's most valuable company, with some suggesting the company is worth more than $1 trillion.
being so dependent on the success of a single product could be a problem.