As someone who works through mobile phone based internet services in Africa and South Asia I agree that in many parts of the world, what you describe is happening, which is great. But there is a huge difference between countries. Just as an example:

Sri Lanka coverage: http://www.airtel.lk/coverage-map.html Bamako (capital of Mali) coverage: https://www.orange.com/en/Group/Orange-in-the-world/countrie...

The uncovered area of Mali is probably 5-8 times the size of Sri Lanka.