O my! You need to brush up on the economics of these markets, companies are really attacking these markets on the mobile front. It is just that you don't hear about it in TechCrunch because it is very business oriented applications rather than social networks or photo apps. Since most people could not afford desktops or laptops cellphone penetration rates are very high and most innovation is done on the sms level. Blackberry is kicking butt in South Africa since they give unlimited internet for around $10 a month, which is huge since most could not afford to get internet in their phone. Take a look at mixxit's growth.

Also, something like square would be excellent for the so called spaza shop market. GPS applications for rural transportation, since most of the workforce use rural transportation and also easier payment methods. There are huge profitable markets to penetrate.