No one knows what they are doing

When you realise no one knows what they are doing, and no one has it figured out. and the majority are just regurgitating what they have seen or been taught. Life is real but our reality is entirely fiction. Why is it that if you say something enough time for a substantial period of time you become an expert on the subject? Someone is an expert; know they just did one thing many times. They might not be the best or great but just the fact that they have done that one thing for an extended period of time makes them an expert.