Question: Would the world not be in a better state if everyone had and continued to follow the example of Jesus?
Maybe you should first elucidate "instructions of Jesus". It seems most people pick-choose the teachings they want to remember but forget the lessons which have no place in a civil humanistic society.
On a basic level if you infer these instructions are of love and forgiveness, then yes the world would be in better shape if we all followed that tutelage - however Jesus did not invent these traits. We all know how to love and forgive, therefore we do not need instructions from Jesus or anyone else.
Also, there was nothing written about Jesus for many years after his death, therefore his teachings could have been lessons made-up to give us all visualization on what life to lead. To that end we should remove the celebration of Jesus as a prophet and more focus on what he might have stood for.
How would the world be a better place? Forget Jesus and create your own ethos based on the morality which lives inside.