Lack of reciprocal action is called self deterrence. Or in simpler words, it's what happens when you keep doing what the bully at school asks you to do, more and more, because he could escalate, even if you are as strong as him or stronger.
The key is that the measure must cost the aggressor more than they gain, and of course be reasonably proportional.
Plus, even if we stick to your irrelevant requirement, response is better. It is less bad to have no subsea cabling for everyone vs making no response and ending up with only the aggressors having subsea cabling.
But of course you can't /know/ the outcome beforehand, which is what makes it a high-stakes game. The only thing you know is that if you keep doing nothing they'll have no reason to stop.