this is where your thinking is flawed and actually only exists because of the viper. Ill break it down for you...
Your argument would be great...If China's interest in the J-10 platform wasnt waining. It effectively at the mercy of any export orders, can you guarantee that in the next 40 years China will support the J-10 platform? Because i can guarantee that the US/LM will.
Where is J-10D going to be built? Considering once again, China is no longer interested in domestically supporting the J-10.
This is flawed actually, because the idea behind your logic is flawed to begin with.
If the J-10 has shorter lifecycles, there is no point in an MLU, or a long term support network, because the platform just wont exist long term. The F-16 is literally here for another 40-50 years, designed to operate alongside the latest and greatest, whereas for China, the J-10 is a bottom tier fighter, with zero long term prospect for it, hence why the waining interest in the platform.
In 10 years we'll end up like the JF-17 has now, price hikes and shortages for spares, oem support waning, frustration and the desire to look elsewhere.
The best example to disprove your argument is the shorter lifecycles of Russian Equiptment- its even more alarming considering the Russian kit has far more options for support via the ex ussr states, yet, struggling for spares, struggling for upgrades, struggling to sustain...etc
So no, 1 F-16=3 J-10c's doesnt work, unless you're certain China will still be producing the J-10 in 20, 30, 40 years- which, surprise surprise, it wont be. Infact unless they get some orders, i doubt they'll be producing them by 2030. Its the same trap the Indians fell for with the M2K...