Basically one of the core issues with a competent government trying to ‘win hearts and minds’ is reaching people. Rural and isolated areas are the absolute hardest to deal with, because it’s hard to secure the area, hard to reliably communicate, and hard to construct infrastructure in the area. Without those three tools - security, propaganda, and material improvement of conditions - securing hearts and minds is a very difficult task. Infrastructure is more difficult to construct in isolated areas, but essentially infrastructure in all cases benefits from economies of scale - it’s much cheaper to build one major project for 100,000 people than 100 small projects for 1,000 people each, or worse, 1000 small projects for 100 people each.

You see this in the (successful) attempts of the British in Malaysia and the (unsuccessful) attempts of the Americans in Vietnam - the ‘strategic hamlet’ program sought to centralize populations so that they could be secured, means of communication could be supplied, and then the population could be won over with material improvements to their lives. You also see this to a lesser degree in Iraq and Afghanistan - Coalition forces had their strongest support in cities which could be secured and improved at a reasonable cost of investment (and amongst areas that would suffer from sectarian conflict if the national government fell, such as the Kurds and Tajiks).