I agree. Pearson took over a team that was in what is really the Third Division and got them into the Premier League for the first time in ten years. There were hiccups along the way but they were the fault of Paulo Sousa and Sven.
Contrary to common belief boards are too slow to sack managers. We have all worked with people who are not up to the kob and it becomes apparent very quickly. The boardwill soon know whether managers are up to the job or not. If not get them out as soon as possible as happened with Martin Allen and Paulo Sousa. If a manager is clearly up to the job you keep him.
It is simple. A good manager does nor become a bad manager.