Barthez is a great example. He had a good first season with Man U and once Howard arrived he went to shit and was never the same again. Started taking too many risks as he panicked to stay No. 1
With respect to Coupet -the competition between him and Barthez for the national GK spot essentially led to a fight between Coupet and Domenech when Barthez got the nod ahead of him. That's the problem when you have two guys of similar skill competing for a position - one has to lose the battle and it can sometimes come down to a coin toss or off field factors more so than who is doing a better job.
Professional sports persons often come with big egos so it's not a good situation.
It's bad enough at national level but at club level it's a disaster because players are contracted for longer duration and have to play a lot more games per season.






