System disruption strategy does not focus on entities, but upon the systems by which those entities exist. You must dissect your targets into a set of individual component, identify the key components, and evaluate their vulnerability.
Every target you want to disrupt depends on a system. If you cannot access the target itself, you can certainly access many components of its system.
A wall is not wall, for instance, it is the materials which it contains; bricks, cement, plaster, etc. It is also the process and personnel which convert these materials into a solid structure. That is its “system”.
You cannot build a wall without bricks or cement, or without workers who perform each stage of construction. Furthermore, each component of the system, is itself part of a system. The bricks have to be supplied and transported to the building site; the workers have to come and go to the site as well, so on and so on.
Multinational corporations are critically reliant upon highly interdependent complex systems, and require the continuous smooth flow of those systems. Even if a specific facility, or a specific key executive, is inaccessible, the system the company depends upon is so large and interconnected that it is impossible to protect every component.