Well, this is how it is supposed to be. When everyone in the first world began dumping 2G/3G, then they would only start to develop handset with a new minimum standard which would then get adopted by developing countries. As long as the old standards remained, there would be those who will continue on the old technology and not adhering to the new standards.

This is the same problem that plagued PC for decades now which allowed ARM to catch up with X86.