In my opinion, you can't make people kinder.
And why should good people die out? In general, of course, evil, aggressive people may have more chances than friendly, benevolent ones, but if everyone is a good person? You definitely can't say for sure, can you?
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal