It's important though to mention that you don't need KYC to attach a real identity to a bitcoin wallet. It's harder to do at scale, but if you're interested in finding the bitcoin wallet(s) of a specific person, or the person behind a specific wallet, this can be done with analysis of the blockchain itself and information from other parties to their transactions (which include their ISP, the ISP of some Bitcoin nodes where they advertised their transactions, and the seller sending them physical goods if they are using BTC for that). Also, if a BTC wallet is linked to a physical identity at any time, all past transactions of that physical identity can generally be discovered, often even if they are using separate wallets.