Let's flip the argument around and try: 'by targeting users in more affluent regions, and using state of the art technology to deliver engaging content, you can make more money'. Does it make economic sense to go with a simpler site and accommodate users from poorer regions? How does that affect revenue versus using the latest eye candy and targeting iPhone users?

If a business doesn't care about users in developing countries, that's their call. I don't think either way is wrong but the front-end people should at least raise the issue and then go with what the client needs. So many websites target a relatively small geographic area that they can safely ignore Opera Mini users and continue to thrive.