[apabepa]

Yes I agree for the general case and I have seen this problem many times where management refuse to see the problem with anti-social loners holding too much of the competence in a team.

It can also depends on what kind of software you are working on. Some parts might require a 'brilliant mind' to push through a spike solution for certain areas. This individual should not really be in a "normal-happy-scrum-team" though, that would be a punishment both for the team and the individual...