Shenhua also said this as a reply in the comment section underneath that quote-post:
本当面白: Here's a question - Why couldn't the south (Chengdu AC) keep increasing the production rate (of the J-20)?
Shenhua: IF the combined (Chengdu + Shenyang) annual production rate of 5th-gen fighters can reach 180-200 airframes (in the coming years/future), (the efforts required for) switching over from existing fighter models to new fighter models, plus retraining fighter pilots (to fly these new fighter models) also puts huge pressure on the fighter squadrons (and the PLAAF as a whole).
(Yes, I bolded that "if" word because I know some people are just gonna jump the gun when they see the "180-200" figure claim.)
For one, I certainly don't think that Shenyang AC's capability to build close to, if not similar number of 5th-gens as Chengdu AC is currently doing once their new production site is up and running is out of the question, should the need arises.
Despite this, it should also be noted that depending on the progress of the J-36 and J-XDS (alongside the realistic needs of the PLAAF and PLANAF as a whole), there are chances where we may not see China's 5th-gen production rate reaching as high as stipulated by Shenhua above.