A team with high performers will get things done but probably will also have big egos. The high performers might gravitate to the hardest problems or become the most visible individuals of the team thus making everyone else just a shadow. Unless these high performers are very situational aware and empathetic the experience might become draining for everyone else including the external team members. Having to rely on a reduced number of people or giving shade to everyone else makes it really hard for everyone. Unfortunately this is very common on many projects where there is a single person with seniority and multiple just starting their careers or perhaps with no depth in the required skill set. To get out of this situation, active effort must be placed to ramp up knowledge and skill either by training and coaching existing members or bringing additional senior members that can reduce de load for the singled out performers; preferably both things must be done.
On the other hand a high performing team is a very rare situation where each team member knows their strengths and weaknesses an also about the other team members. On these kind of teams, each member knows when to lead and when to follow, also when to push through difficulties and when to ask for help. The egos are in check but also the skills are deep and varied. To find yourself on a team of this characteristics is really a rare opportunity and should be used as a learning experience. If you have a team that behaves like this, then make it evident and have all team members celebrate it.
In an organization where there is a high performing team there will be forces that will change team dynamics as throwing more work to the team or trying to break apart the team to create more high performing teams. An additional situation is that high performers tend to have offers from other organizations all the time; your organization might not be in a position to contend with all poaching attempts. There is no clear way to proceed here but as always context is important to know what needs to happen next. For my part, I'm happy to have been part of such teams and also happy when team members left to improve their lives elsewhere. Trying to take a note from the Netflix book (No rules rules), I try to look it as a sports team, I will not lie, it is hard to do but it is needed.