Earlier quoted context omitted.
How is digital currency, in general, anonymous? Bitcoin records all of your transactions, publicly, essentially forever. If at any point in time there is a way to tie your identity to _any_ of the transactions made in your lifetime, then all of your other transactions get deanonymized retroactively. Maybe you made a mistake, maybe a bug is introduced into the Bitcoin software, maybe the government passes a new law, e…
Right. I mean, basically you're as safe as your public-key/username. If you can make your wallet in some kind of very off grid way, the same way you'd have to use Tor; cash laptop, McDonald's wifi, etc.
But that's not very realistic. If bitcoin were to become the primary way to pay for things, you're going to be buying physical goods with it. If you order something online then they have your shipping address to associate with your wallet. If you buy something at a physical store then they can see you and know what wallet paid them.
And lets say you maintain one wallet for the secret all-digital stuff and another wallet for everything else (or however many wallets makes sense for you), it's better that way, but all you have to do is slip up once with the secret wallet to be screwed. Everything you did with that secret wallet can now be associated with you even if the transaction happened 20 years ago.