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Well, it's very possible that when you purchase at a grocery store, you just pay with Bitcoin and they'll never know who you are. But what about the point where you purchase that Bitcoin? Sure, most of us use our bank to purchase Bitcoin on an exchange, so at that point, we've already revealed our identity to the exchange. Since the government regulates exchanges and banks, they could obtain that information.
Of course when we use centralized exchanges, we are usually revealing our identity specially nowadays that almost all of them have KYC. But what if we stopped seeing bitcoin as something we have to buy with our fiat and start seeing it as a currency, just like the way we see fiat.
You are already part of a signature campaign. AKA a job that you are getting paid for. Those coins are only linked to your account and not necessarily to your identity (you could use TOR for example). In other words when bitcoin is used as a currency (not an investment) it also provides a high level of privacy.