Alternatively, one component of a superintelligence that makes it super might be a tiered mind that's capable of processing far more input streams simultaneously to get around the core human inadequacy here, that we can only really focus on one thing at a time.

The same way we can build "muscle memory" to delegate simple autonomous tasks, a super intelligence might be able to dynamically delegate to human level (or greater) level sub intelligences to vigilantly watch everything it needs to.

But security advancements scale.

On average, today's systems are much more secure than those from year 2005. Because the known vulns from those days got patched, and methodologies improved enough that they weren't replaced by newer vulns 1:1.

This is what allows defenders to keep up with the attackers long term. My concern is that AGI is the kind of thing that may result in no "long term".