Anonymity is not a binary thing. It is very, very far from it. Have you heard of the letters the IRS has been sending to crypto traders lately? Only about 10,000 Americans have received a letter from the IRS asking about their unpaid taxes. Only 10,000! And those people are probably Coinbase customers who have large volumes of trades. There are millions of Americans who own crypto. 10,000 sounds like a very low number. I'm betting a small fraction of crypto-owning Americans have reported all of their taxable crypto income to the IRS.
The internet is a vast ocean of data. Going after one person with the tools available to the likes of NSA/CIA/whaterver is expensive. I seriously doubt data collecting companies know every bit of our online behavior. Throwing care completely out of the window because "anonymity is already an illusion in the modern world" is overreacting. Not everyone potentially interested in what we do with malicious intent is as powerful as one of the alphabet organizations.
To each their own; you certainly make some good points.