Nope. A2A is not the only way. S2A works just as well, as as the attacking force, the chinese will be forced to have A2G commitments that the IAF wont.
Sure, runways can be destroyed for both. If both are ineffective, then IAF has prevented PLAAF from doing much
Thats called a defensive victory.
Sure. I think we stand very favourably compared to China. You know why? Defenders advantage.
And something you dont seem to know - We have more gun artillery than china does.
Rocket artillery I dont know the exact figures, but the chinese advantage is not as high as you have imagined it to be in your mind.
AMCA is the solution, it is very relevant to the discussion. Lack of AMCA means we stay entirely defensive, and simply force PLAAF to do airstrikes with only J-20s. With AMCA, we can do offensive defense with our own deep strikes.
ARM are not a solution for everythiing, even USA with its heavy emphasis on SEAD, and complete air dominance, was unable to fully silence iraqi anti air assets. Chinese, with no dedicated platform, wont do any better.
As for replace quickly, that is the point - We can replace with our own + other countries. They cant.
There is good reason to overestimate your enemy, prepares you for worst case scenario. But scare mongering by assuming worst case scenario is just stupidity and does not help.