Seriously. Companies retain these people because they provide value despite their poor social skills. Why shouldn't they keep them, if that's the case? If only those with good social skills were employable, the workforce would be cut in half.
Overall value of one person to a company is hard to measure. Yes, they might write great code, but if their abrasive and asshole personality bring down the productivity of the other five developers on the team, is it worth it?
Probably not in that scenario, but plenty of anti-social types manage not to bring down the productivity of everyone around them.
If someone's social problems are destroying their value to the company then by all means they should not be employed there. I simply strenuously object to the blanket statement that all anti-social people should be completely unemployable regardless of circumstance or value.
