No kidding. I've worked with a few people who have done bicycle advocacy in West Africa (through the awesome https://bikesnotbombs.org/). They learned that West Africa is awash in cheap used bike frames - it's about the only part of the bike that is eternally repairable. Instead, the finer parts eventually get chewed up and need to be replaced. Things like ball bearings, derailleurs, chains, and tires eventually die. Wheels last a long time, but also have a limited life.

This project (and other ones I've seen, like bamboo bikes) generally only create bike frames, the one part that won't really help the developing world.

To the cardboard bike's credit, the wheels are pretty cool. Find a way to make brake pads, chains, tubes, and tires from locally sourced or recycled materials, and you'll really be on to something!