I tend to think the reason good teams rarely lose 2 in a row is because good teams rarely lose, period. If football games were as simple as throwing dice each game would be a discrete outcome, with the probability of one completely unaffected by the previous outcome. With sports I don’t think you can completely discount the psychological effects of a loss on the players, and injuries that happen one game can have impacts that carry over to the next, but I still think the “good teams don’t lose 2 in a row” thing as a product of extra motivation or focus is overstated, if it exists.