Every package gets updated, when there is an update for it. Dependencies don't matter for that.
Only if a package depends on a specific version of another package, is there a difference. When the dependency would get updated to a version that doesn't satisfy the version requirement. Then an error gets thrown and nothing gets updated.
But the package maintainers for the official repos don't really let that happen. It's more of a problem with aur packages.
Ich dachte, dass wird Lobbyismus geschrieben.