Senior engineers are exactly who I trust to "just fix it" when they notice a problem, even one outside their immediate domain. Sure the bar is higher, but that's still their job. If this was about staff or architects, then it would make sense.
As I go through this thread, one word keeps coming to mind: discernment. The more senior you become as a SWE, the more you’re expected to know what to address, when, and how to address it. The actual addressing of the problem is table stakes, and as you move from senior to staff you’ll find yourself directing more and implementing less.
For example, we run a Jenkins instance for our platform that has bi-weekly production releases. We write announcements in slack when there was a release with a list of PRs and links to the tickets in Jira. That used to be manual work. At one point I was annoyed by it and took 30 minutes to write a 15 line script to automatically take the merged PRs, create a Jira link and announce it in our slack channel.