The security world overemphasizes (fetishizes, even,) the "advanced" part because zero days and security tools to compensate against zero days are cool and fun, and underemphasizes the "persistent" part because that's boring and hard work and no fun.

And, unless you are Rob Joyce, talking about the persistent part doesn't get you on the main stage at a security conference (e.g., https://m.youtube.com/watch?v=bDJb8WOJYdA)