Per equipment needed to set up a game, soccer is way cheaper than disc golf, as you only need one ball for a match. Last I checked, a recreation quality soccer ball ran less than $20, less than the cost of a DX starter set.
Problem is that most third world county residents can't even afford that. I've been told in the slums of many foreign countries, they will make their soccer equipment (balls, goals) out of whatever is available, even packed balls of dirt. Its from these pickup games that most third world countries procure their national soccer team. Oh, they'll set up a stadium and hand out nice jerseys for that. Soccer matches provide a means for these countries to give their citizens a means of distraction from the destitute squalor around them.
Unless we've actually seen these third world outposts, we Americans simply haven't the slightest clue what rock bottom poverty is. Even most 'poor' Americans are richer than most people on this planet. Our "cheap" by their perspective is still prohibitively expensive.
Look mate, basic requirements to play soccer include a ball, shoes and maybe some goals or something set up as goals. To play disc golf all you need is a disc and TREES. That's it. You don't even need shoes really. Most 3rd world countries are starved for agricultural space so fields could be at a premium, whereas you can disc golf ANYWHERE. You throw a disc at an object, it gets no cheaper.