I believe you actually need to sit down and think about it in a global scale, and then you will realize just how wrong your assertion is. Of course, that depends on what your definition of "succeed" is. If like most people, your definition revolves around climbing the ladder and becoming upper-middle class, or part of the rich, then yes, there is a finite number of "successes".
Besides, class size is a limited resource, as is employment opportunities.
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A rising tide raises all boats, but you can't raise the tide without taking the water from somewhere else to begin with -- somewhere else there is less water because you wanted to raise the tide in your special place. If you can't see there are other boats somewhere else sitting lower, it's because you aren't looking outside your limited view.