The massive spending of USSR during cold war years was based on the people's tolerance and endurances the hardships of USSR eg. The shortage of food, an idle economy and many social problems! I dont mind if those unconveniences occures to achieve a military balance! But the Chinese society will protest and resista,they will  became violalence after enduring a very bad economic downfall! This is something you cannot ignore! In real practice 500 or 1000 ICBM/SLBM wont help much the military balance and nothing possible to really use those nuclear missiles