This is why we don't talk about work in public forums - its too easy for discussions to get out of hand particularly when only a fraction of the information is public.
I had my own work put on hold at the start of the week - increase the risk on something that is going well to 'fix' something that seems to be going off plan (in my case). 2 different projects, threads aligned on different deadlines, different commercial impact resulting from predictions of progress.
The more competent developers (particularly in larger organisations where there is more flexibility in the planning) are always at risk of diversion due to illness, failing plans or requirements changes - comes with the territory.
Coding/programming skill is always going to be a limited resource. It is innate, for the ability that matters. It *cannot* be taught. It is a creative talent, and therefore is subject to all the human weaknesses of sports, media, etc...
If a winning fund manager quits, sell your shares, because the winning gambler has quit. In baseball, losing the star pitcher is the same. The list goes on.