While these recent experimental and theoretical polariton photochemistry works are exciting, there has also been concern expressed about the extent to which these proposed modifications can be realized when many (N ∼ 10 3 -10 6 ) molecules are collectively coupled to the cavity . Some polariton photochemistry experiments in the collective coupling regime have failed to observe cavity rate modifications with theoretical explanations typically assigning blame to the presence of the dense manifold of the dark states or cavity loss. Many of the previous theoretical works predicting cavity modification of photochemistry used simplified model systems with only a single stronglycoupled molecule, a set of disorderless molecules, or assume a perfect lossless cavity for analytic and computational convenience and consequentially cannot address the issues of dark states and cavity loss. For example, previous theoretical work on PMET, particularly the works of Mandal et al. in Ref. 21, uses explicit quantum dynamics simulations and analytic Marcus theory rate constant expressions for PMET with a single molecule strongly coupled to a lossless cavity mode. Mauro et al. in Ref. 22 described analytic Marcus and Fermi's golden rule (FGR) rate constant expressions for PMET with many identical molecules strongly coupled to a lossless cavity mode, as well as simulated PMET population dynamics with a kinetics model that included cavity loss and dark state transfer with FGR.