I have wanted for a long time to see some quantification of these security features, i.e. "What percentage of attacks does feature X prevent in the real world?"

I have wanted for a long time to see some quantification of these security features, i.e. "What percentage of attacks does feature X prevent in the real world?" and "With all these features combined, how much longer can the OS survive attack vs without them?", but I don't think I've ever seen it.