Owing your success to the group does not imply that the success itself is a guarantee. Just that without the group, the odds are many many times worse.
I would argue that the degree to which you owe something credit for your success is the degree to which it guarantees that success. If my society/group/family guarantees my success, no matter my actions, I owe it everything. If it makes no difference at all, I owe it nothing.
If it merely improves my odds, then I owe it something, but there must have been at least one other factor at play, and that factor is also owed credit. I presume you would call that factor something like "luck". No doubt that that plays a role, but credit for luck belongs neither to the society nor the individual. All that is left, then, is individual choice, and so the rest of the credit belongs to the individual.
For the purposes of this thread we are obviously assuming free will exists. If it doesn't then achievements have no meaning and credit belongs to no one, making the whole conversation moot.
