The structure would survive anything tossed at it by VN PH BN IN and MY.
10 metres thick of concrete? That far exceeds the most extreme structures built for similar purposes.
A dumb bomb lands, does minimal damage to the 10 metres of reinforced rebar and concrete, and the strategic value remains.
These structures are explicitly designed to withstand a regional clash over the islands, but are specifically not designed to withstand the US or JP navy.
So you agree that any bomb on the island with or without structure will be an attack on sovereign Chinese soil?
You do know that in WW2, 10 ton grand slam bombs penetrated the 7.2 m RC u-boat pen in 1945?
. Just saying, you just need a big enough bomb.
Now, lets say you are right, what strategic equipment do you think will be placed inside those structures? missiles will be rendered useless by blast shock waves. electronic warfare equipment is fragile. Normal gun turret? its hardly strategic at all.
The strategic philosophy; those structure don't matter in a regional war, one shot on the island, the PLAN will be sailing down. As you also said, individually, or combined, VN PH BN IN and MY cannot challenge the PLAN in a full brawl.