Answers are typically out of date and no longer good practice. Some claim that the ability to edit answers fixes this, but all it does is subvert the accept/vote functions. You end up with strange "Ship of Theseus" answers where what is written has nothing to do with what was so highly voted, or what solved the original problem.
Where SO goes wrong is that they have tried to create a definitive set of answers in a field where the real answers change yearly, or even monthly.