It seems extremely relevant. Your argument suggests the president need only appoint a subordinate who will themselves give the desired illegal order without the president's public command. In the unlikely event the subordinate is called to account, the president can simply pardon them.
This is certainly not a hypothetical "parade of horribles", since Trump has already pardoned military officers convicted of war crimes.[1]
> A lot of these important projects have a single point of failure - who is the president every four years. I wonder how we build institutions and resources resilient to that?
We already did. The legislative branch allocates funds for stuff that the people deem worthy. That budget becomes law. The Constitution says the "President shall take Care that the Laws be faithfully executed." There's even a specific law that prevents the President from withholding Congressionally-approved funds.
What you are seeing here is not a lack of designed resilience, it's the wilful removal of that system.
On the contrary, there appear to be good legal arguments that Hegseth merely saying "no quarter" is, on its own, a war crime:
https://www.justsecurity.org/133970/legal-advice-hegseth-no-...