When Apple Inc. launches its much-anticipated 10th anniversary iPhone this fall, it will offer an unwitting lesson in how much the smartphone industry it pioneered has matured. The new iPhone is expected to include new features such as high-resolution displays, wireless charging and 3-D sensors. Rather than representing major breakthroughs, however, most of the innovations have been available in competing phones for several years. Apple's relatively slow adoption of new features both reflects and reinforces the fact smartphone customers are holding onto their phones longer. Timothy Arcuri, an analyst at Cowen & Co, believes upwards of 40 percent of iPhones on the market are more than two years old, a historical high.