Except TW TFR even worse than PRC TFR, and ultimately scale effect takes over - PRC with crippled TFR still generates about as much male new borns per year than TW has men 18-40 total. PRC still on trend to generate 3-4x more MEN than US projected to add population per year, incidentally around the same as active duty military... having enough bodies is not going to be an issue for decades. Having enough nukes is.
I disagree, bodies is not limitting factor for PRC, it also becomes cheaper to wait for TW specifically because TW male 18-40 is set to decline = less kill bots / occupation force needed. Attacker:defender ratio (i.e. commonly 3:1) = every defender TW loses due to demographics, PRC with same TFR will come out significantly ahead, will need less enforcement:civilian ratio for occupation.
But ultimately, it's about hardware+industry - current trend = regional force balance shifting in PRC favour vs US+co every year with no end in sight. PRC better off accumulating capabilities at scale, not just regional, but global (i.e. prompt global strike) and increase autarky (less net population + more electrifcation = more calorie + energy security). All trend incentivizes waiting and building.
TLDR waiting and building becomes less costly (or rather less risky) to pursue PRC's ultimate strategic goals associated with TW scenario... displacing US posture out of east Asia and perhaps hitting CONUS infra at scale as response to US intervention. The latter part is key, there are important stretch goals to TW scenario that secures PRC geopolitical interests for 50-100+ years. It's much more important to be able to tackle those "costly" scenarios "cheaper", where cheaper is also relative to making intervention much more expensive for adversaries, i.e. PRC "winning" hand in TW scenario is to show US posture in east asia not sustainable, and CONUS (including TSMC Arizona) not defendable.
I'm not arguing against that at all. Just that if the PRC wants it's best chance, the clock is ticking. It becomes more costly the longer they wait.