Some of the best managers don't adapt to their players as much as they shape their squads and select players based on their own vision of the game. If Sarri is great enough to demand such freedom, or whether clubs like Chelsea will give that to him is very much doubtful.
About the bold part, sure. At Barcelona, only a great motivator would be able to make the likes of Messi, Suarez, Pique, Busi etc. work hard after they've won so much in their careers. Doubt Sarri is one, even though stylistically he's the right fit. There is also the slight possibility of these players having a stroke of ego after the recent bad results in Europe and decide they need to do something about that, but it's pretty slim. They do the talk, but don't put up.
