Most large companies encourage testing in prod. It's called split test. Clearly precursor to that is staging, and precursor to that is integration tests and whatnot. But none of that catches what you can with a/b test, and great monitoring.
Don't get me wrong, where I work they definitely are open to making mistakes in production. We roll out "risky" new features with split tests and I think we use that logic well so this notion obviously exists, but I'm not sure how widespread it is.
Feature testing is one thing, but you can go a/b testing a whole binary between new and old version to catch interesting bugs too.