This type of thing happens in all countries, not just in the third world, there are "lazy" people who, for some reason, do not want to log in to an online casino, or do not like to go to a physical casino, or They simply do not have access to the aforementioned, but they do have access to these bookmakers, which you can access by text message, a phone call (old school) or they simply make an assigned betting route, neighborhoods, communes, urbanization, whatever where you are and they take your bet, but not only that, they take your home address, work address and worse still your privacy.
One of the "advantages" that this type of bets have with these "mobile casinos" is that when you are a customer they give you credit, then, a phone call, the text message (MSM), Whatsapp, Telegram, are enough to receive the size of your bet.
This issue has nothing to do with your region, nor the particular story you tell, it is common sense, we even recently experienced a case of betting with sports "agents", as happened with Shohei Ohtani's assistant.
Even though I agree with you this kind of issue is not exclusive from developing countries or the so-called "third world". I believe it is more likely to happen in those countries, I instead of developed countries, because of how the justice system operates and how quickly moves in countries within the European Union l when compared to other countries. Also, even if I am overestimating the speed of the law in developed countries, there is also the fact there is crippling corruption in countries within Latin America and Africa. So those who are behind the betting place could bribe authorities for them to not get effectively prosecuted by not giving the money they own to the winner of those bets.
It is something I would not expect to read coming from Spain, for example.
I believe the national and societal context of these cases is important.
Also, I agree with you. I don't quite understand why people risk to have a lackluster gambling and betting experience with devious services when they could easily sign up on online bookies of very good reputation. To each their own, I guess...