Developing software is about a lot more than just writing code.
One of the most important aspects of a great software development team is their ability to cooperate in a meaningful way that increases quality across the team.
If the members of a team don't invest in a culture of achievable quality, then the code will suffer.
By achievable quality, I mean not only a standard to work towards but also the context and guidance to achieve that standard.
In many ways, that context and guidance is more important than the standard itself, since without it the standard becomes meaningless.
If the members of the team who fall towards the lower end of the skill spectrum aren't given meaningful tools, guidance, and feedback to meet an agreed upon standard of quality, they won't be able to deliver.
Furthermore, I've noticed that some people become paralyzed and unable to deliver if there's a standard being set that they don't understand. It ends up creating a sense of fear that whatever they're doing won't pass this nebulous standard of quality.
There are many ways to set a rigorous standard and encourage everyone's participation in its enforcement, and all of them rely on careful communication that makes the standard achievable for everyone.
The end result is a team that not only holds themselves to a high standard, but understands that a culture of quality emerges from the actions of individuals cooperating to achieve it.