[adventured]

Your occam is incorrectly structured. Power/comms is irrelevant to the equation in question, imploding, and doesn't add.

It imploded later requires only one failure (the structural failure), just as the relatively short time duration option requires only one failure. Right away is also a later event.

We have no way of knowing what its structural true condition was in terms of whether it was more likely to make it a very short duration or something more like a day.

[aqme28]

You're completely ignoring that the comms went out. All we know is that comms went out early, and debris was found later. What single failure would cause both of those pieces of evidence?

[oefnak]

You're right, I think, but we also know that several ships heard sounds after the communication loss. You'd also need to account for that with your theory.

[dboreham]

One ping only.

[EA-3167]

As others have pointed out, there were multiple, redundant failsafes on the ballasts which would have led an intact sub to surface even if the crew were incapacitated or dead.