red velvet is going to end up exactly like girls generation and f(x). Sm knows that some of the members won't renew, even if they continue as a group it will be just for name sake like fx and snsd.
everyone was expecting a group comeback sm went for joy solo instead and they did it for a reason. sm wants to transfer fans redvelvet to aespa. they are giving rv solos to keep fans stuck around but no group comeback so that they will support aespa in the meanwhile while hoping for a redvelvet group comeback. sm won't directly disband redvelvet because it will make fans angry and they won't support aespa, sm wants this transition to happen slowly.
