Be honest.
To me it is that the overall country situation, no schools and people very little interested in being smart and know things, created a state where the old heads are still there and only few can benefit it, despite Fally, Fabregas and Ferre making more views and being more known thanks to the social medias era, it is very hard for them produce classics and be remember the way Koffi, Werra and jb are to you why?

I'm not sure either. Other countries in Africa are producing music not sure how memorable though.

It is a factor of things.

It is because our western countries blocking any efforts of really giving a chance of foreign music such as Congolese music to get exposure because they want to make sure that "White" artists get more recognition. Also like you said, the country is a mess with no government and no culture that has respectability. With that, comes many Congolese artists who are so desperate to look more "marketable" such as Fabregas, Fally Ipupa and some others. Ferre Gola is the only one who at least tries to maintain some originality of Congolese music.

Finally, we live in a period that music does not have too much importance. Many Congolese are more interested in controversies and stupidities rather than genuine music which poses a big time. It is not unique to Congo. It is also true in my country USA, Canada, Russia, Colombia, Mexico and others.