In what ways, and for what reasons, did people think that cybersecurity had failed?

Mostly that it's just so hard to keep things secure. Organizations have been trying for decades to ensure security but there are continuous failures and exploits. One person mentioned that one third of exploits take advantage of security systems themselves.

What techniques from cybersecurity were thought to be relevant?

Don't really remember any specifics, but I think formal methods were part of it.

Any idea what Mallah meant by “non-self-centered ontologies”? I am imagining things like CIRL (https://arxiv.org/abs/1606.03137)

I didn't know to be honest.

Can you briefly define (any of) the following terms (or give you best guess what was meant by them)?: * meta-machine-learning * reflective analysis * knowledge-level redundancy

I remember that knowledge level redundancy involves giving multiple representations of concepts and things to avoid misspecification/misrepresentation of human ideas. So you can define a concept or an object in multiple ways, and then check that a given object fits all those definitions before being certain about its identity.