Why don't we get reputation for answering community wiki questions?
What is meta?
- Any Stack Exchange user can ask a question
- The community provides support, votes on ideas, and reports bugs
- Your voice helps shape the way Stack Exchange operates
Because the answer is "owned" by the community and not any one individual (even more so than usual).
Making an answer CW is supposed to encourage others to edit it and make it "the" answer to a question, so then the problem would become - who gets what proportion of the rep from up-votes (or loses what proportion from down-votes) if the answer were still "owned" by the individuals.