Absolutely, if management is entirely invested in it, and it becomes a mandatory part of the process (e.g. updating the wiki is a part of a release or new build), it can be a critical resource. The problem is that the organic nature of wikis lead to people believing that it will just emerge, in the same way that the relatively unstructured wikipedia eventually became a critical resource.
But citing wikipedia is often folly. The man hour to output ratio of wikipedia is absolutely enormous. It is an extraordinarily inefficient process that works because there are millions of people moving, structuring, contributing, making templates, rewording, reorganizing, etc. Eventually greatness emerged.
