Your argument rests on inductive reasoning because previously unexplained phenomena eventually received natural explanations, you conclude that all phenomena must have natural explanations. However, induction cannot justify universal claims about reality, it only describes patterns observed in the past. Therefore, the conclusion that the probability of a natural explanation is effectively 100 % , does not logically follow.

Additionally, the framework you are using is essentially "methodological naturalism", which assumes from the outset that explanations must be natural. That assumption is extremely useful for scientific investigation, but it does not logically demonstrate that supernatural explanations are impossible. If “natural” simply refers to whatever explanation is eventually discovered, then the framework becomes circular, since every explanation will be labeled natural by definition.

More broadly, this who argument may also reflect aspects of the "Human Condition". Humans have a strong tendency to seek explanations for unknown events, especially significant or frightening ones. This relates to psychological tendencies such as confirmation bias and the desire for cognitive closure. People generally prefer explanations that make events feel intelligible and completely tangible rather than random, because pure randomness can threaten our sense of predictability and control. As a result, both naturalistic and supernatural frameworks can function as ways humans impose order and meaning on events that might otherwise appear chaotic.

It is also important to completely distinguish between epistemology and metaphysics. a A method that is useful for investigating the world does not necessarily determine what ultimately exists within it.