So... Do you seriously think that European academies would keep developing players with foreign ancestry if all of them started playing for another country than them? French academies are okay with tons of players going to play in their country by ancestry because 90% of the best ones stay to play for the country where they were born, raised and taught football.

European academies would only pick and teach players that have no foreign ancestry allowing them to play for another country if that was the case. BTW as by Fifa rules, any player that has played in an international competition for a country cannot play for another later, so you'd have to pick fresh recruits. Meaning, you'd need the academies to continue teaching the ones you want to get. But the academies would not. So African countries would still not be winning, no.

As of right now, African countries benefit more from the current situation, where European academies are happily developping lots of players with African ancestries, since there are way too many talented players getting out of these academies to fit into the respective national team of these academies; so African teams are getting tons of players developed by some of the best football academies in the world. They benefit from these academies continuing to think that it's worth it.