smtddr parent
Now, let's take those 3 points and consider a 3rd world country with interwebz-censorship or very poor infrastructure and no forseeable future where it'll improve to anywhere near what most first-world countries have. Cellphone coverage is the easiest thing to setup in those kinds of environments.
Do you have any examples of such countries where at the same time SMS will still work and be cheap enough to be viable?
Even most countries in sub-Saharan Africa has at least GPRS - most of them have 3G. Some of them are deploying LTE. Certainly there will be areas where for some time still there will still be limited data access, but the question is how many of those areas actually has functioning cell coverage.