What is Public Service?

Thomas Sowell writes to college students who want to change the world and tells them what real public service looks like:

You want to see more people have better housing? Build it! Become a builder or developer -- if you can stand the sneers and disdain of your classmates and professors who regard the very words as repulsive.

Would you like to see more things become more affordable to more people? Then figure out more efficient ways of producing things or more efficient ways of getting those things from the producers to the consumers at a lower cost.
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Those who have helped the poor the most have not been those who have gone around loudly expressing "compassion" for the poor, but those who found ways to make industry more productive and distribution more efficient, so that the poor of today can afford things that the affluent of yesterday could only dream about.