Krebs investigations' overwhelmingly rely on reused emails and phone numbers across services which he follows back to some account they registered in 2008 in their real name. This is very effective because he is investigating cybercriminals who 1) have been at it for a while and have left extensive trails and 2) don't really care that much if they are identified because they can just stay in Russia. In the Alphabay and Silk Road cases, they relied on similar techniques (AlphaBay welcome emails sent from Cazes's hotmail, "altoid"/Bitcointalk/Shroomery posts in the case of Silk Road). These kind of things can be prevented by making a new email with a service that doesn't require your phone number and your real name.

In the recent Monopoly Market case and seizures from the huge hacks, it was all chain analysis. Only the Bitfinex hackers even tried to conceal what they were doing (by using Alphabay as a mixer, which became their undoing once it was seized), the others went straight from crime -> accounts in their name. This can be obviated with Monero.

Yes, I'm aware that the US government used some sort of probabilistic attack on Monero in 2018 against North Korea, which has since been fixed.

I don't want to spend my whole life looking over my shoulder and IRL opsec is a whole other thing that I am not really familiar with. I don't use the techniques in my post because I'm not leading a double life or something like that, but I think it's entertaining to read about.

Edit: Also, is your contention that there is no Internet anonymity anymore, therefore it's fine to even further limit Internet anonymity?