You don't seem to realize that having a lot of senior developers on a team can cause problems because there's no hierarchy. That's why junior developers and es

You don't seem to realize that having a lot of senior developers on a team can cause problems because there's no hierarchy. That's why junior developers and especially medior developers are very useful. Medior developers have quite a bit of experience too, they just haven't become leaders yet. Especially if your team size is a bit larger you will not want it to consist of only seniors. Also having explicit leadership positions for dev teams is questionable, especially for senior developers, product managers who are used to calling some of those shots.