You wouldn't necessarily be able to extrapolate any meaningful inferences out of a situation like that, given the parameters you set. Anyone who has a ton of power in their hands has the possibility to win any fight and beat any fighter on the planet. The key thing to factor in is the probability of success; just because a knockout punch is possible that doesn't mean it is highly likely to occur. Therefore when trying to infer the implications of the hypothetical scenario of Kimbo knocking out a fighter like Fedor or any other meaningful mma fighter, it is important to to also contemplate that if they were to fight on multiple occasions what are the possible outcomes and of those outcomes which ones have higher probabilities of occurring. Therefore in the spectrum of possible outcomes in a Fedor vs Kimbo fight there is a scenario where Kimbo wins via knockout, but given their comparative skill sets there is a higher probability that Fedor wins via submission, Tko or knockout. As a result the meaningful inference is that the most probable outcome is Fedor winning and therefore gives merit to the superior skill set of an elite mma fighter to that of a street fighter with limited mma experience.
In many ways this is similar to the Ray Mercer vs Tim Sylvia fight and the James Toney vs Randy Couture fight. In the Mercer Sylvia fight a retired professional boxer knocked out one of the top heavyweight mma fighters of the current era who was a former champion and a few fights removed from a title shot. Mercer was able to do this with the first punch he threw. In the Toney vs Couture fight, Randy Couture took down and submitted with ease one of the greatest boxers of all time who was in the twilight of his career. When evaluating the implications of these fights there is evidence that supports that a boxer can beat an mma fighter with ease and that an mma fighter can beat a boxer with ease. What isn't factored in is the totality of outcomes of each match up. For example there was and is the possibility that Sylvia could have submitted or tkoed Mercer and there was and is the possibility that Toney could have knocked out or TKOed Couture. But even though these other scenarios are possible, they may or may not be probable and in turn make it difficult to accurately assess whether s boxer can successfully transition into mma,
Hypothetically what would have happened if Couture decided to get into a striking exchange with Toney? What would have happened if Toney knocked out Couture in the first exchange and embarrassed him on the feet? Would you be able to extrapolate from that that any boxer can beat any mma fighter with ease? No you wouldn't. You would look at a scenario like that and say that it was a possible outcome and therefore should be anticipated as a possible outcome in a scenario like that. But it wouldn't discredit all of the techniques in mma, it would simply support the fact that boxers are dangerous fighters and that mma fighters have a lower probability of success when in a striking exchange with a professional boxer relative to taking them down and submitting or stopping them with strikes.