Is the Scrum Master still needed on highly mature teams?

Every team must have a Scrum Master, but there’s nothing to stop the SM from applying focus onto his or her service to the wider organization.

In my mind it is like a sport team and the case when they win the tournament every year and even here you have to have good and perfect coach. The same is the Scrum Master. If everything ok now it doesn't it will be always forever.

In my mind it is like a sport team and the case when they win the tournament every year and even here you have to have good and perfect coach.

Briliant analogy. Always new challenges to face, plateaus to break or arrogance to overcome. 

The Scrum Master is mandatory Role regarding to the Scrum Guide.

So yes, the Scrum Master is always mandatory -full stop. This role is not linked to maturity, success or any other attribute of the development team.

If you apply Scrum without this role you dont do Scrum, you do "Scrum but".

@Alfredo stole my thunder.  I have used that same analogy many times. I also use it to illustrate how a Scrum Master coaches and not manages.  Sports coaches will often draw up "plays" and then coach the players on how to execute them. But that is usually done based on the best circumstances.  The coach must also help the players know how to react if the other team has the right defense in place for the play. You coach them on how to inspect, adapt and continue to move forward towards the goal. 

As many have said, Scrum without a Scrum Master is not Scrum.  Yes, mature teams could require less coaching but teams are never without a coach of some kind.  Scrum Masters on mature teams should be focused less on helping the team to improve and more on inspecting the team for practices that adversely affect them. Adverse practices will be best adapted if there is someone there to help coach and facilitate. 

In the book 'Scrum Mastery: From Good To Great Servant-Leadership' Geoff Watts says the goal of a scrum master is to create self-sufficient teams. He points to a specific example: a scrum master is 7 minutes late to the daily scrum. When he arrives the team confront him as to where he's been. They explain they are frustrated that the meeting had to be delayed while they wait for him and now that he has arrived they can finally start.

The role of the scrum master is to facilite a team and to champion scrum values. The problem with the above exmaple is that the team has become reliant on the scrum master instead of achieving self-sufficiency. Watts argues that a great scrum master aspries to making the team self-sufficiently excellent. If the scrum master is not available and the team grinds to a halt then is the team truly self-empowered? Watts says that the biggest compliment for a scrum master is to be taken off the team as the team feels they no longer need a scrum master to make the process work.

Despite this, scrum does have overhead. Someone needs to keep the relationship between the product owner and team strong. Someone needs to protect the team from external pressure to break process. Someone needs to champion scrum at all levels of the organisation, else the organisation runs the risk of losing the benefits of scrum as it is warped and bent to the whims of what the most senior member demands this second; much to the detriment of the developement team and the quality of the product.

I think the answer is broken into 2 parts. Part one is the day-to-day faciliation of scrum. As a team matures they will not need the scrum master like they used to for this purpose. At the start the meetings will need to be organised and the team will need reminding of the goal of the meeting by the scrum master. As a team matures they should facilite this themselsves. They should understand and achieve the purpose of every meeting and feel motivated to attend without an external influencer. Once the team is in this mature stage the scrum master can step away from the day-to-day running and focus on part two: the organisational championing of scrum. The scrum master is still available should the team need them. It is also good to have an external eye evaluate the team from time to time as they may spot something the team has missed/overlooked.

Should a Scrum Master be viewed as a hired gun, who is there to quickly make changes and make an impact on an organization right away, not obsessing about a few broken eggs here and there or should a Scrum Master be a permanent fixture in an organization that is there to help transform the culture of an enterprise and engender change throughout a company/institution and that he/she is not only there to make an immediate impact but to ensure that the change is lasting?  

A Scrum Master is not to be treated as a 'hired gun'. S/he is a 'servant leader' and someone who knows the Scrum framework so well that s/he is referred as the 'master'. The role was created not to merely fill any space or gap, but to make sure the framework is implemented well in the organization.

I repeat what you've already mentioned in your question @Jayant: "...  a Scrum Master be a permanent fixture in an organization that is there to help transform the culture of an enterprise and engender change throughout a company/institution and that he/she is not only there to make an immediate impact but to ensure that the change is lasting"

We must not forget, a Scrum Master is someone who is a 'friend, 'philosopher', and a 'guide' - and may play roles of a mentor, coach, teacher, guardian, technologist (if s/he is from technology background) ... and more, as required!