If he's not incarcerated, my next guess would be that he just got bored with bitcointalk and moved on. As I said, he's very bright and articulate and those gifts are wasted on 99% of people here who don't have the literacy level to appreciate them. True, he got a lot of merit in a very short period of time, which is evidence that at least some of the members here appreciated his writing, but I have no doubt that much of his output few over the heads of the ever-present throng of shitposters--IF they even tried to read what he wrote.
He also could be deceased. Bad things happen to talented people all the time, but since I don't think anyone here knew him IRL, there's going to be no way of knowing this unless he returns.
I have a strong feeling guess #2 is the correct one.
I've seen nullius posts. He really seems wants to have fun on the forum and maybe you are right that he is not getting what he wants and got bored here. because of how the current forum situation is. Tho whatever that be his lessons were properly distributed and he returns then that will be a start of a new learnings for us.