If you are born as a serf in a feudal system then being willing to work twice or thrice as hard doesn't guarantee success or even safety from near-starvation.

If you are born as a serf in a feudal system then being willing to work twice or thrice as hard doesn't guarantee success or even safety from near-starvation. Hard work alone can only guarantee success in a perfectly fair and even system, and obviously not even the west is anything close to that.