Next-generation iPhones likely to focus on internal improvements.
BlackBerry Overtakes iPhone as Bestselling U.S. Smartphone in Q1
1. BlackBerry Curve (all 8300 models)
2. Apple iPhone
3. BlackBerry Storm
4. BlackBerry Pearl
5. T-Mobile G1
BlackBerry also offers multiple models which are also represented on the top sales list. NPD attributes the surge to a number of factors including aggressive giveaways as well as broader availability of the BlackBerry across the four major U.S. national carriers.
The data is interesting to see after there have been persistent rumors that Apple might try to expand the iPhone's market penetration through both a "Lite" version and support on additional U.S. carriers. DaringFireball's John Gruber believes that Apple will model the iPhone product line expansion after the iPod's:
Apple went on to repeatedly improve upon the iPod in two ways: on the high end by producing new devices with the same shape and price but with new features (additional storage, color screens, larger screens, video, etc.); on the low end by taking the existing features and making them smaller and cheaper.
The reason why Apple did this with the iPod, and why I'm convinced they'll do it again with the iPhone, is that when it comes to managing the balance between per-unit profit and overall market share, Apple is determined to err on the side of market share.