The fact that someone was recommended by a chain of people doesn't mean that good, or even competent. Perhaps the old CTOs weren't competent to judge or didn't have enough experience to have a proper baseline.
It's quite possible that I could judge someone at some task (say cutting & laying intricate tiles), and think they're quite good. They may seem fast to me because they're doing something that would take me forever. But if you brought in a real professional, they may laugh and say worker is going to slow.
The author said that the coder in question didn't show any improvement after 2 weeks of coaching. The developers at the previous firm he mentioned were slowly improving, that's why he kept them. From my reading I got the impression that if the PhD candidate had improved, he would still be there.
It's quite possible that I could judge someone at some task (say cutting & laying intricate tiles), and think they're quite good. They may seem fast to me because they're doing something that would take me forever. But if you brought in a real professional, they may laugh and say worker is going to slow.
The author said that the coder in question didn't show any improvement after 2 weeks of coaching. The developers at the previous firm he mentioned were slowly improving, that's why he kept them. From my reading I got the impression that if the PhD candidate had improved, he would still be there.