As shown in this graph below, the descendants of BA2.86/JN.1 do indeed have a transmission advantage over JN.1. However, they are increasingly finding it difficult to gain ground on JN.1, as evidenced by the decreasing exponential growth of recently emerged variants.
Due to the persistent dominance of JN.1, virus transmission occurs too slowly, or in other words, the immune pressure from highly C-19 vaccinated populations on virus transmission remains too high.
The only possibility I see for the virus to break through this pressure is a sudden and drastic change in the glycosylation profile of the spike protein.
This change will be of such a nature that it enables the virus to overcome the inhibition of virus virulence by non-neutralizing antibodies. In this way, the virus will be able to spread and replicate fully, not only from one individual to another, but especially within the same vaccinated person.