10 years since a land-based FC-31 first showed up.
PLAAF showed no interest, but PLAN launched 2 aircraft carriers over those 10 years, so operational needs (i.e., circumstances) change over time? Plus, the SCS and Taiwan situation got really hot, so the security environment (i.e., circumstances) change over time?
Perhaps FC-31 with dual engines are costly to procure and maintain in meaningful numbers, defeating the purpose of "high-low" mix like F-22/F-35. WS-13E engines may not be mature then too. Therefore, the PLAAF showed no interest.
However, the PLAN only needs a handful of navalized FC-31 onboard their aircraft carriers, so the benefits outweighs the cost, as it would exponentially improve the airpower of carriers with a 5th gen onboard compared to J-15T.
Yes, this is true. However, I am MORE worried that China will soon have 3 aircraft carriers but not a single 5th gen prototype by now. J-15T is fine, don't get me wrong, but that's a lot of money spent on 3 aircraft carriers that doesn't have a potent 5th gen weapon to counter the US navy.
The J-20 development programme was supposed to cost $4.4 Billion. So we can expect a navalised FC-31 programme to approach this in costs.
That is probably the same cost as the Shandong carrier which just went into service.
But given that there are only 2 ski-jump carriers and that future carriers will be catapult versions, there was no point in developing a new naval 5th gen fighter earlier.