It seems to me that, even if you believed in the notion of a meritocracy, it would be awfully difficult to establish whether people have "succeeded" entirely on their own merit or because of other factors. Those that don't like the idea of egalitarianism tend to argue that we already have a meritocracy because it is the people of ability who naturally rise to the top,, and that those people's contributions are of greater value than anyone else's.
I've been reading George Monbiot's book "How did we get into this mess?" and he makes the point: "even when outcomes are based on talent and hard work, they don't stay that way for long. Once the first generation of liberated entrepreneurs has made its money, the initial meritocracy is replaced by a new elite, who insulate their children from competition by inheritance and the best education money can buy."
He goes on to suggest that if innate ability and hard work are or should be the sole preconditions for success, then those who espouse such a notion should not try to load the dice in favour of their own children.
In any event, I think the idea of "success" and "value" is very much a subjective judgment. Is a job necessarily of more value to society because it is well paid and of high status, and should "success" be seen merely in those terms? My view is that a society that respects people equally, treats them decently and which values everyone's contribution will, in the long run, be a happier and healthier one.