Simple- Because in this highly competitive era when where are so many lunatics running rampant, it's hard to find good reliable help and Trump being much more professional than most of the recent presidents is being diligent in searching for the help he wants.
Right - and then firing anyone who doesn't kiss his ass. Part of being president is appointing competent advisors and then listening to their advice, but it doesn't appear that Trump has gotten around to either of those.