Sure it does. A secret stops becoming a secret once you give it away to enough people. I feel like you're trying to justify piracy but picked the wrong argument.
I'm talking about personal data. Piracy is rarely a concern here.
(And btw, piracy only makes the data less valuable, because you lose the ability to sell it to someone who already has it. Not because the game or movie etc would become less enjoyable.)
(There might be other concern, eg around privacy, about giving your data away. But worrying about value isn't really one of them as an individual.)