It's relatively simple to use random credentials everywhere and to completely disconnect your hacker persona from RL.
Or is it that we only hear about those that do this...
2. Proper security takes time and effort, so there is less time to devote to actual business, which means they are less likely to be successful at a scale that makes them widely known
You only defend the ones who get caught! By definition you never defend one who hasn’t been caught doing something suspicious.
For the first decade of their career they're really only facing people who will bust them if they're totally stupid and deliver themselves to the authorities practically gift wrapped. Because the flip side of most criminals being lazy is that most police are lazy. But then after a decade they wind up with someone at least mildly competent getting interested in them and they've left traces all over the place.
What Krebs is suspiciously silent about is who provided (il)legal protection for the service. I guess this type of dirt on Russian officials is collected to a different folder inaccessible without clearance. Hence the framing of the lone Robin Hood story.
1. We've entered the full on "Oh shit, you don't need to be a hacker to do computer crime" phase of computer crime. Smash and grabs, just pay some disgruntled employee for their credentials, hire people to do the tech bits you need done - you don't have to be a 1337 hacker to get involved with this stuff. So they may not care or even be aware of much forum opsec.
2. Does Russia care about Russians ripping off other countries? How hard do you have to try to hide it if you just dump the username and move on when you're found out because there's not any repercussions from local law? I don't think anybody is going to go to Russia and get them any time soon.
If they're already infamous, it's too late for them. This dude seems to have been a real amateur; he not only re-uses passwords, he re-uses usernames in his passwords. He puts his birthdate in a password. He doesn't have a clue. He seems to be a low-grade criminal who should have stuck to fencing stolen goods from a lockup garage, but stepped out of his league.
I imagine that date is in a lot of Russian passwords. That was the day of the '91 coup attempt against Gorbachev.