For bitcoin to be efficient there is a need for minimum technology for example pc and a good internet connection, this is the reason why bitcoin is not a solution for every country. I am sorry to say this.
To make bitcoin efficient there is no need to do anything because it is already efficient enough. What you are trying to say is probably the transaction possibility and that will need basic devices and internet connectivity. Now considering the fact that everyone has at least an android smartphone and at least a 3G connection if not more than that - that much is covered.
Whether it is a solution or not is far from speculation but we have seen some countries develop their own cryptocurrency like Venezuela and although its making a splash this may be the emergence of something new in this niche.