Because VERIZON IS A SERVICE PROVIDER, NOT A HARDWARE MAKER! I know I greatly prefer my Samsung i760 to the iPhone, but if I had to have an iPhone-like phone, I could get one from HTC, Samsung, LG, and several others.
Here's a better question: why is Apple so lacking in integrated business solutions like the Windows Mobile, or even RIM platforms? Why did it take Apple 18 months to finally get 3G, when Samsung, Motorola, and LG had it for that long?
The iPhone was released one year ago today, June 29, 2007.
Apple stated at the time that 3G was too power hungry as currently implemented—consuming energy at two times the rate of the 2.5G EDGE network did—and it had too small of coverage area (less than 3% of AT&T's customers could access it). One year later, the 3G chipset consumes far less energy and AT&T's 3G coverage is approaching 10%. Apple is also releasing the iPhone 2 in countries where the coverage is over 50%.
You would be surprised at the number of integrated business solutions that have already been announced for release with iPhone 2.0 on July 17th—many of them developed by the same businesses that developed for RIMM and Windows Mobile but using Apple's SDK that makes development far easier.