Because nobody does, and it is not for lack of trying. Wikis demand that busy people write down what they know and keep it current. Heidi captures knowledge as a side effect of work already happening, and keeps it alive automatically.
The wiki failure mode is universal: enthusiasm, then decay, then a graveyard of pages nobody trusts because half are outdated and nobody knows which half. The maintenance cost is the flaw, and it never goes away.
Heidi inverts the model. Meetings, chats, and tickets flow in on their own; consolidation and cleanup are her job, not yours; and every fact shows its source and age, so trust is inspectable instead of assumed.