Note that in 320.23, for AC cable run across the top of the floor joists, an accessible attic is one that has either a permanently installed ladder or stairs, or one that requires a portable ladder. Each of these two scenarios has different protection requirements.
The question is if access is blocked by permanently installed equipment/ducts, etc., is the attic considered accessible anymore. I'd think - purely opinion - that If a human can't even get in there to hoist something through the attic opening without dismantling permanent stuff, it would not be considered accessible. On the other hand, if people can access the attic opening and hoist things into it even if they can't climb into the attic, then the protection requirements for a portable ladder would be applicable. All of this does raise some questions about when the wiring was installed, how was it installed, and how was it inspected.