I always wondered about this, and figured I was missing something. If every transaction is recorded for eternity, then tracking funds is just a matter of linking wallets to individuals, which while that may be difficult, it's not impossible. Certainly not with the kind of funds that three letter agencies command.
I always assumed the closest you could get to anonymity with any blockchain based coin is to use a burner wallet, and convert it cash as soon as the transaction is complete--but that's just using cash with extra steps.
And the fact that it's recorded for eternity means that maybe you don't have enough information to link people to the transaction today, but the information will keep accumulating...
Monero solves this with ring signatures. Every transaction is automatically signed by a lot of wallets and there's no way to tell from which wallet the coins are actually coming from.
I always assumed the closest you could get to anonymity with any blockchain based coin is to use a burner wallet, and convert it cash as soon as the transaction is complete--but that's just using cash with extra steps.