Two, the general tone of the advice is "plan things well in advance" (compensation, structural adjustment etc.). The fact is that you can never plan everything well enough in advance, especially things like structural adjustment. The article doesn't address what to do when your plans inevitably "collapse in the presence of the enemy".
Three, it is a fact that you can't simply fire an executive just because it is obvious to the wiser people in the company that he's incompetent. He will have plenty of friends and will be sure to raise hell for it. This is a sure way to get lots and lots of politics, and of the most unpleasant sort too. Oftentimes, the only reasonable solution is a "structural adjustment" - create a sinecure for the guy where he has few responsibilities and can safely slide into irrelevance.