A growing number of tech experts are predicting that the iPhone is in danger of losing the "smart phone wars" to an upstart operating system from Google, in a dramatic reversal of fortune for one of the world's coolest hi-tech products.

For many people the iPhone is still the last word in digital chic. Its sleek style and touch screen changed the way many used their mobile phones.

Next month Apple's device will be launched on a second phone network in the US, making it available to millions more customers. The news has created a huge buzz and some have whispered that Apple might one day become the first trillion-dollar company in the world. So this should be a great time for Apple's irascible chief executive Steve Jobs. Or it would be if not for the growing commerical clout of Google's Android.

"Too late for the iPhone," read one headline last week in a Daily Beast column by tech writer Dan Lyons. Many experts agreed. "Android has taken over from what I can see," said Will Sullivan, founder of the website Journerdism, which is studying the mobile technology industry. Some commercial statistics bear that out. Android phones are now outselling iPhones in the US. Latest figures from the US show the Android and iPhone neck and neck in market share – but with 40.8% of new smart phone sales in the six months to November going to Android and 26.9% to iPhones.

Critics say that the iPhone's launch on the Verizon network is too late and that it relied too long on the patchy service provided by AT&T. That has allowed Android to take off at such a speed that it has left the once cutting-edge iPhone in its wake. "It was almost comical how much people said they hated AT&T," said Rob Jackson, editor of Phandroid, a tech website that tracks the Android market.

But the greater problem lies with the real differences between iPhones and Android. While the iPhone is the whole package of network, technology and phone, Android is an operating system that many different phone models can use. That gives users of Androids a huge variety of choices about how complex (or not) they want their phone to be. Meanwhile, iPhone users are essentially bound to what Apple alone allows them to do and buy.

"Personally, I prefer Android. I like to change things around to suit my needs. But if I was recommending my mom to have a phone I would recommend an iPhone," Sullivan said. In his article for the Daily Beast, Lyons was even more succinct about the limitations of the iPhone. "[It] is a bit like the situation you had with Henry Ford's Model T, where you could have any colour you wanted as long as it was black," Lyons wrote.

Indeed the iPhone has always had critics. Mark Zuckerberg, founder of Facebook, last year took to his own Facebook page to slam the device for having a poor battery and dropping phone calls. "I got four chargers so I can keep it charged everywhere I go and a landline so I can actually make phone calls," he posted.

But not everyone is writing Apple off. Verizon will open the iPhone to 100 million new customers in the US. There is also no doubting the excitement that many people get from products created by Apple. "It arguably has the strongest brand in tech. It is cool. It stands for more than just a phone. It is a fashion statement. It is a lifestyle," said Jackson.

That is important. For one of the great ironies of the development of the smart phone market is that making phone calls on the devices has been supplanted by email, instant message and chat. A vast business ecology of "apps" has also grown up allowing smart phones to do anything from checking the weather to picking out a local restaurant. In this new world of mobile communications many think it would be foolish to make firm predictions. "So much can change again in five years that I just don't know what will happen," Jackson said.