[0] Slightly tangentially, to be ignored, until later (after careful reconsideration of doubts raised in your [1]: https://economics.stackexchange.com/a/29610[2])
In particular, to consider how unification of the 2 notions of excludability/rivalry can lead to the 2 actions of subsidies/taxation coalescing (thus going "beyond good & evil")
[2] >>43621295
[4] https://www.econlib.org/the-correlation-between-excludabilit...
>Yet in the real world, both excludability and rivalry lie on a continuum.