According to China Defence Blog there are so far 48 WZ-10 active in the PLA and that means that CAIC can produce about 24 WZ-10 each year. Now that the WZ-10 has become the main anti tank platform and the WZ-19 the main scouting platform. What is going to happen to all those armed WZ-9 and WZ-11's ? Are they going to be "relegated" to rescue and auxiliary tasks ?
I doubt it, the Z9 airframe is not exactly famed for it's carrying capacity or endurance, and it would only be of limited use as a utility helo, and it lacks the dedicated winch to use for S&R. Although it is possible that we may see the PLA Mi-17/171 fleet be used more exclusively for transport and logistical support missiles while WZ9s take over their original attack and air assault missions as more and more WZ19s and Z10s come online.
In my view, the existing WZ9s will likely continue to operate alongside the new Z10s and WZ19s in the recon and attack roles. We have already seem pictures of Z10s escorting WZ9s, and I think that is how the PLA will use them, with WZ19s taking over the bulk of the scouting missions while the WZ9s and Z10s operate alongside each other to complement and supplement each other in the attack and air assault roles.
The WZ9s, in addition to bringing more anti-tank missiles and unguided rocket pods, could also embark special forces or regular troops to give the attack formation an airborne infantry capacity that just the Z10 and WZ19 would lack by themselves.
By the time the PLA has built up enough WZ19s and Z10s that operating costs become an issue, the older WZ9s would probably be nearing the end of their service lives and can be retired to relieve pressure on the budget.