The article describes in detail how the lack of technology inspires and encourages an inventive spirit. He calls them "hackers" because tinkering and inventing is so prevalent in the group as a whole.
It may not fit your own definition of technological progress, but it's true all the same.
The phrase "re-inventing the wheel" comes to mind, the definition of progress is moving forward from the current, not artificially handicapping oneself the past and then working back towards the current. My statement is extremely easy to refute, but I see no examples in the article which show they have advanced the forefront of technology.
There is no doubt that these people are creative and tinker, it just seems to me that their efforts are wasted, or at least extremely sub-optimal.
It may not fit your own definition of technological progress, but it's true all the same.