The value of an individual mining reward is very small relative to all extant bitcoins. When you mine often enough, the value of your reward is rightly comparable to the amount of work you've done, all the goal and nongoal calculations averaged together. If Bitcoin rewarded lucky stiffs unduly it'd be unfair, but it's proven rigorously that it doesn't, it rewards committed laborers.

Authors get paid for the thousands of hours of writing, not just for the time it takes an uneducated typist to copy out the final text.