This observation doesn't only apply to games development, but also to software development in general, e.g. web apps. If every developer working on a project is

This observation doesn't only apply to games development, but also to software development in general, e.g. web apps. If every developer working on a project is specialized (DevOps, backend, frontend - even for frontend there are some that only specialize in HTML/CSS and some in JS), they tend to only concentrate on their domain and lose sight of the big picture of how the app should work (or never have that big picture at all), which hurts the quality of the finished product.