The answer is I do not know either. Why? Because history remembers those who treat people below him/her and give them the respect that all humans deserve far better than their peers do. And it remembers them fondly.
I guess we become great for how we treat people 'below' us well; not for how well we treat our 'masters' or people 'above' us. Not saying butlers aren't good people. It is just that history rarely remembers people who treats those 'above' them well. They may be well-paid by their masters. They may be well-recognized in their master's inner circle but it is just not the same. Being the greatest butler at Buckingham Palace may stabilize your livelihood but it doesn't inspire a lot of people - if at all it does.
That's why the likes of Ali, Mother Teresa, Nelson Mandela, Muhammad Yunus and Karpal Singh are such great icons that epitomize the greatness of the human spirit.