They are relatively cheap for what they represent. They are cheaper than buildings and if you only have buildings, the Americans quickly come demanding you hand them the keys to everything otherwise they'll knock it all down. Silos keep those bastards away.
Decoy silos are even cheaper. You do not actually need to do much work for decoy silos. It's just the surface that require attention and make sure you give the satellites a good show. For some decoys the depth needs to be correct and you do need to put a cannister in. SAR satellites can do wonders these days. Well the Chinese SAR satellites can. No doubt the Americans having done it sooner would have some abilities in helping figure out which silos are legit. Low end decoy silos work against some, not against others. You can have a mix of full functional or full depth decoys and a mix of surface only.
The silos could also be totally functional but unarmed with missiles. There could be a new DF-5 ranged ICBM for new silos who knows.
The conversation in China a year or two ago was not so much discussing whether the nuclear expansion is necessary or not. As soon as the US policy shifted on China around 2017, the writing was on the wall. The Chinese leaders saw it and seem to have put some plans into action as soon as it became clear the US would be redirecting all their psyops firepower on China. Stupid and naive Chinese were talking about whether or not nuclear expansion is necessary as some here have also made hopeless arguments for keeping warheads around 300. Well the people actually working on China's nuclear program hinted that expansion was always only waiting for new generation of weapons. Why build more DF-41 using old warhead designs and nuclear weapons when you are about to put HGVs on the majority of intercontinental ranged missiles? Why use old warhead designs and weapons when new ones are available. Extreme radiation weapons like neutron bombs are old news. There must be far more effective and destructive world enders available for the top three nuclear nations. The others certainly aren't staying still, old warheads on new HGVs? I don't think so. Would you put an old diesel truck engine you used in the past into your newly developed sports car?
I suspect that new weapons, warheads, delivery systems are all ready and completed, hence the rapid expansions now. Rumours of new silo based ICBM. HGV equipped ICBMs (actually an old rumour already). JL-3 being tested and Type 094 changes.
(Dong Fang electrical, one of the big boys)
