I've spent some time with Papa Simaro some years back in his home. He was still pretty active, but you can tell his career was winding down; now we're here.
Let's be honest, who in Bana OK could he give the band to? There were no known stars. The stars he did have: Pepe Ndombe has passed on, Josky is sick and is basically retired, Shakembo and Elba defected and went to Europe, are mostly in their 60s. Shame on him for not grooming someone, but who was worthy of that honor? You also have to look at the other popular bands who have lost leaders in the last 20 years. OK Jazz is now run by Franco's son (who doesn't perform at all) after Youlou suffered a stroke, Empire Bakuba and Victoria Eleison are quiet and Tabu Ley's L'Afrisa International is defunct. Perhaps Bana OK could've went to Baby Ndombe, but he hasn't been productive.
As for Manda being Wenge, I have YET to see a younger Wenge generation singer who sticks to the Wenge format. Many of those singers embrace the Odemba style so I can see how easy it is for Manda to transition especially since he's already been singing Dalienst's songs. I say give him a chance.