The ZTZ99 production actually wasnt that small.
As of 2013 we have at least 600 ZTZ99 in their different variants confirmed (ZTZ99-1, ZTZ99-2, and the new and heavy ZTZ99A), with more ZTZ99A (formerly known as ZTZ99A2 in fanboy-speak) being produced to equip heavy mechanized regiments in the Northern MRs.
Plus we have 2500 ZTZ96 series tanks in service with different units elsewhere in the country.
But people here are basically right: China is neglecting the armor modernization - there are still many vanilla ZTZ59 (original 100mm gun, no stabilizers, no night-vision) in service even with suppossedly elite mechanized and armor regiments facing North Korea.
The reason is simple: China is concentrating its PLA Ground Force spending not to replace its obsolete tanks, but on upgrading C4ISR, organic air-defenses, army aviation and mobile artillery. A Chinese mechanized division/brigade may be equipped with obsolete tanks, but they are increasingly seeing themselves being supported by digitalized self-propelled artillery, tactical UAVs, increasingly sophisticated air-defense systems (some of them are even suppossed to be equipped with AHEAD munitions capable of taking out guided ordnance in mid-air), networked command and control assets, and quasi GA organic attack helicopters like the Z-9WA, Z-10 and Z-19. The tanks are just a mere placeholder.
