[reyme]

If Our new head coach is so good then why no other test or associate team approached him to be their head coach? Why he did not find any team in IPL, big bash or county team?

It's not anything against him. Do understand gameplan, team selection,
batting order, bowling rotation, basic field setup according to game situation,
change in gameplan according to the situation, captaincy guidance are all head
Coaches job. We saw serious flaws in such areas in the last 3 games. He was also with the team in India series.

Just like it takes time, experience and hard work to be a good player, same applies to a coach as well.

It will take at least 10 years for the new coach to be become a world class head coach.
Every Test Team and even the top associate team should have world class head coach.
Experience is that much valuable. You give team Austria under a very ordinary coach and they will fail too. There is a reason Srilanka did not hire him as a head coach.

How a coach can make a world of difference are evident in many teams. A good experienced coach can turn a very ordinary team into a good competitive team.