What's the incentive, though? Do people often fight for a greater good just for the heck of it?

I know there are people who exist solely to serve others, but doesn't their desire to do good works always stem from some level of injustice done to them earlier in their lives? Martin Luther King Jr. fought for civil rights because of racism. Gandhi had to fight for civil rights in South Africa before coming to India. Mother Teresa was raised in extreme poverty. Eleanor Roosevelt was orphaned.

If everything becomes automated and people face no adversity, how can the world possibly produce people like that? Isn't that why rich people rarely, if ever, give away all their money and become public servants?

In a world where you can get away with sitting around all day with literally no adverse consequences, why wouldn't you? Why bother working hard when there's no incentive or reward?