Some people don't need the higher data speeds since they spend most of their time near Wi-Fi hotspots, or they only use the phone for email. I for one don't need it a 3G phone right now, as most of my use is near WiFi, and when it is not, it still blows my friends Sprint phone away.
Also, many people are confused, thinking that the 3G phone won't work on the EDGE network, which is untrue, it will work, just like the current iPhone works on the old GPRS network.
TEG