Right, but the PLA is infamous for holding onto ancient hardware. And it's only half a decoy, because it doesn't matter how a 500kg warhead got there once it hits. An obsolete but functional missile poses a legitimate threat to overstressed air defense; they can't just let them hit targets for free. Given the PLARF's ratio of launchers to missiles it seems unlikely that they are in need of divesting excess stockpiles.
J-6/7 UCAVs are a different story since the maintenence requirements for aircraft is more significant. But there's still some utility to be found in terms of target drones, training, etc. When it comes to suicide runs, those platforms were never designed to be single-use, unlike missiles.
Holding onto ancient hardware in regular service if production of modern hardware has yet to enable replacement, is different to holding onto ancient hardware in regular service for purposes of serving a decoy role.
Keeping old hardware in service poses costs twice.
First it requires the direct cost of personnel, basing and maintenance.
The second cost is the opportunity cost of where those personnel and basing and maintenance resources could have been used if a more capable and more modern system existed instead, which can result in actual worsening of your overall combat efficiency.
That's why mothballing old systems makes sense rather than continuing to operate them, if your production of modern hardware enables old systems to be replaced. It's because eventually it's the personnel and basing and those associated costs which becomes the rate limiting factor and you want to transition them to a more modern capability rather than spending money on them to be retained as operational "decoys" or as a way of drawing defensive fire.
If the concern is wanting to improve penetration capability of fires, the PLA today have access to technologies and systems that present far more effective ways to do so than resource intensively keeping old SRBMs in service.
The J-6 ucav situation is similar in nature.
