I agree that not all failures matter (most don't, in fact). On the other end of the spectrum, I know of a bunch of seed/series A startups that basically operate under a model where they ship everything and fix the stuff people complain about. As long as you do that fast enough, the median user experience is pretty good, because only the first n% actually see the problem before a fix is live.

I'll go out on a limb and guess that at a hyperscaler, shipping a bug to prod means hitting canary or 1% of traffic. Seems fine!

I think my point still stands, even as the shape of failures shift. There's certain ones that still hurt (data corruption, exploited security holes, etc.) because they're hard to notice. It might even be that the primary goal of ownership is to develop intuition about where those failures are likely to happen.