As an addendum, it seems to me that you may not necessarily need a 'long-term planner' (or 'time-unbounded agent') in the environment. A similar outcome may also be attainable if the environment contains a tiling of time-bound agents who can all trade across each other in ways such that the overall trade network implements long term power seeking.
Concepts that I intend to use or invoke in my writings later, or are parts of my reasoning about AI risk or related complex systems phenomena.
Okasha's paper is addressing emerging discussions in biology that are talking about organisms-as-agents in particular, otherwise being called the Return of the Organism turn in philosophy of biology.
In the paper, he adds "Various concepts have been offered as ways of fleshing out this idea of organismic autonomy, including goal-directedness, functional organization, emergence, self-maintenance, and individuality. Agency is another possible candidate for the job."
This seems like a reasonable stance so far as I can tell, since organisms seem to have some structural integrity -- in what can make delineated cartesian boundaries well-defined.
For collectives, a similar discussion may surface additional upsides and downsides to agency concepts, that may not apply at organism levels.