@gloriouscow
I used to read super-nichy miltech journals well over 20 years ago and saw ads for PCB live pathway diagnostics reporting faults in realtime.
Considering I've seen #miltech boards 10 layers deep, it's entirely possible to construct fully realtime, self diagnosing system.
As to your previous post (you prolly already know) the sampling frequency and number of channels would determine feasibility of such a virtual CRO system.
I don't play with #electronics much anymore, so it was a while ago but 10 channels was the most I've seen.
However, your design proposal would be entirely feasible scaling already existing tech.
I think it's still cheaper to have a meatbag diagnose Blinken lights is why we don't see this tech commonly.
Maybe when/if we start building long range space vessels.
Anyway, your post caused an enjoyable thought trigger.