The effect of "meritocracy", at least in this context, is not linear. Every incremental unit of influence or fame (followers, impressions, etc) leads to super-linear influence between some interval (probably tapers off at the tail).

And it is not independent / non-zero sum. If "A" gets more influence, it may take from "B"'s opportunity. And if the growth function is indeed super-linear, then B's opportunity is very quickly squashed.