The non-technical manager isn't able to do more to prevent it. Nor is the busy technical manager. The poor performer either isn't able or willing. There's no Superman coming to rescue you. You are the person on the planet who cares the most about the poor performer's effect on your life, and you know the quote about "doing the same thing over and over and expecting different results". The utility of "blame" is questionable, but the choice is only do you consider yourself a victim of the poor performer with nothing you can do and have the same situation happen again and again, or do you recognise that you are in a position to act and prevent it? (If you want, you can then blame your choice not to act, when the situation predictably recurs, I guess).

https://www.youtube.com/watch?v=n4AUY-v1nsE - "We are going to have to act, if we want to live in a different world"