You are right, and that's why diversity of revenue is a good thing. If tomorrow Office and Windows drop revenue by half, Microsoft as a whole wont drop revenue

You are right, and that's why diversity of revenue is a good thing. If tomorrow Office and Windows drop revenue by half, Microsoft as a whole wont drop revenue by half, and I guess that's the main point the pie chart is making. But I also agree with you that the Pie Chart might not be completely accurate and might be oversimplifying the situation, but I think there's no denying Microsoft is one of the most diversified tech company out there in term of revenue.