On the flip side, why bother spending time optimizing a process if nobody notices when it fails? Aren't there more important problems to be solving in at scenario?
Tech debt filled mud balls where feature after feature is clumped on top of one another without worrying what came before it and what will come after it are not great to maintain. Sure if you don't plan on maintaining or building on the component and you don't care if it restarts, then let it restart forever. But if it's a component that you plan on adding features to for a long period of time and stability issues are ignored, those types of issues can compound over time and make it more difficult to reason about and maintain.
I agree, things that change frequently need more attention to make sure you're not spending more time than you need to make changes.
Acknowledging that I'm changing the goalposts a bit, I would consider a lack of understanding about the lifecycle of an application that causes development delays an abstract form of "noticing when it fails"
Maybe people do notice, but it’s not easy to report back? Or they notice the system runs slowly? Or they just accept the fact that all systems (extrapolating from several banking, public service, and publishing sites) are crap, and need to live with it?