Warren was CEO until 9 months ago. While yes, he's been chairman for 50 years, he's been an exclusive chairman for only 9 months. The role is ambiguous anyways and it's pretty obvious that someone else won't have the authority Warren has. And his son has been a director for 30 years so it's not like he's a new hire

He was chairman and CEO for a long time. Since he has only been a chairman for not that long I don't think it's fair to say that he's been a very active chairman for a long time.

Whose strategy is explicitly to hold good stocks for a very long time.