i'd like to see how you'd be measuring "performance" in this context, or what you consider to be worthy of merit, because those things are not the objective measures you seem to think they are.
people who are contributing to open source projects are not a perfect Gaussian distribution of best to worst "performance" you can just pluck the highest percentile contributors from. its a complex web of passionate humans who are more or less engaged with the project, having a range of overlapping skillsets, personalities, passions, and goals that all might affect their utility and opinions in a decision making context. projects aren't equations you plug the "best people" into to achieve the optimal results, they're collaborative efforts subject to complex limitations and the personal goals of each contributor, whose outcome relies heavily on the perspectives of the people running the project. the idea you can objectively sort, identify, and recruit the 50 "best people" to manage a project is a fantasy, and a naive one.
the point of mandating the inclusion of minority groups in decision making is to make it more likely your project and community will be inclusive to that group of people. the skillsets, passions, and goals that a diverse committee contains are more likely to create a project that is useful and welcoming to more kinds of people, and a committee that is not diverse is less likely to do so. stuff like this is how you improve diversity. in fact, its quite hard to do it any other way.