China will not be looking to match the combined 5th gen fleet around its eastern shores courtesy of Japan and the US. It won't because it's unrealistic to do this in the current economic condition where there are plenty of other areas in need of funding. If a war really starts, just use longer range weapons to knock out those bases. Kill supporting air assets like tankers and AWACS. Then even the latest and greatest will run out of ammo and fuel and have nowhere to land unless a nearby nation allows them to use their airfields, potentially making them into targets too.
Chasing equal numbers is a fool's errand. Chasing technological superiority is worthwhile though but that involves not putting all your available resources into procurement alone.
