Who is he in that sentence? Do you mean the owner of the wallet who is absouletly very lucky, or the hackers that did a lot of investigating and reverse engineering to learn that the datetime was the seed. Was that luck or l337skillz?
It was both, like it usually is. All that investigating and reverse engineering would have been for nought if the program didn't have the problems in the first place. Hard work is often how you capitalize on luck. Sometimes the work is enough by itself, and sometimes it's not and the luck is integral.
Seems like they all were lucky that he luckily used a vulnerable password manager and knew the approximate parameters and time it was created. If he didn't get lucky, they might not have been paid.
Who is he in that sentence? Do you mean the owner of the wallet who is absouletly very lucky, or the hackers that did a lot of investigating and reverse engineering to learn that the datetime was the seed. Was that luck or l337skillz?