The concept of nuclear triad is that, yes, armies very strongly depend on their second-strike capability. So, the game is for the subs to not to become compromised.
> We are not in the 1960s when at times it was literally true.
You are claiming that not only China, but the US and Russia don't have the capability of launching strikes from 30 minutes? (i.e., well beyond the time to respond to ballistic missile launch detection)? Do you have a source for this?
This doesn't appear to agree with you:
https://www.mitpressjournals.org/doi/pdf/10.1162/ISEC_a_0021...
Launch-On-Warning
One source of ambiguity in the implementation of China's no-first-use policy is the ongoing debate in China regarding the pursuit of a launch-on-warning posture. Recent doctrinal publications and Chinese interlocutors indicated that the debate has yet to be resolved. On one side, some members of China’s strategic community argued that a launch-on-warning posture would ensure the survivability of its nuclear deterrent if its opponent has robust targeting intelligence. The Science of Military Strategy states that a launch-on-warning posture "is in accordance with China's long-standing no-first-use policy, and may effectively protect China's nuclear forces from sustaining even greater losses, improving the survivable nuclear counterstrike capability of China’s nuclear missile forces." China's first priority should be to prevent its adversary from precisely locating its missile launch positions. If China is able to reliably ascertain that an adversary has already launched nuclear missiles at China, however, China could quickly launch its nuclear missiles for a counterstrike "before the enemy has been able to actually inflict nuclear destruction." Launch-on-warning would therefore provide China with an option for nuclear retaliation if a nuclear adversary were able to overcome Chinese efforts at concealment, deception, and mobility to ensure that its forces survived a first strike.
What you cited is sad, but firstly it is still an "ongoing debate", and secondly the road from declarations to the actual ability is long with this one. And may it never materialize again.
Do you have a source for that?
The sibling comment says Russia and USA have a prompt alert which can launch in under 15 minutes. Other articles say the US president could be contacted and approve in under 30 seconds, not sure how the Russian chain of command goes.
The decision process does not begin when nukes are detected of course, that's the end of the process. Pre agreed criteria have already been met. Quite likely there is no decision about entering a full scale nuclear war because they are already in one.