This is significant if you consider there are a number of Android phones available for a similar price which are technologically superior to the iPhone 3GS. It also puts Apple's lawsuit campaign against various Android vendors, particularly Samsung, into perspective.
It's hard to imagine how it would be possible to sell more iPhones. Apple already has problems keeping up with demand. What Samsung, HTC, and others are doing isn't taking Apple customers. They're expanding the market, which clearly benefits Apple.
iPhone buyers are overwhelmingly loyal customers who continue to buy more iOS products. Android buyers, on the other hand, are significantly more likely to switch to an iPhone some time after their first smartphone purchase..
More Android buyers means more chances for Apple to sell iPhones. More lawsuits means more chances for them to spend a pile of money. If not for Steve Jobs' irrational hatred of Android because he didn't want anyone copying Apple (even though Apple copies freely), it's unlikely all these lawsuits would have ever been filed in the first place.
With Jobs no longer leading the company, they have an opportunity to put an end to all this wasteful litigation and return to concentrating on customers, rather than the competition. Apple's business model for the iPhone has never focused on selling the most phones. Instead, they focus on selling the most popular model at the highest profit. They have done that for years and there's no reason to believe the iPhone 4S will be an exception.
If they want to compete with volume, that will require a lot more than pushing Android out of the market, It would take a complete rethinking of their business strategy. And to what end? Whether Apple or Samsung is the top smartphone maker depends on how you define that term. And ultimately it is unimportant.
Apple is the most successful company at selling highly profitable smartphones. Samsung is the best at selling volume. There is, and always will be, a need for both business models within the smartphone ecosystem.