Ultimately, even with automated testing, someone has to do the manual testing of checking that it's actually providing the value it's meant to. When you remove

Ultimately, even with automated testing, someone has to do the manual testing of checking that it's actually providing the value it's meant to. When you remove the manual QA team and switch to staged rollout, you are moving the manual QA burden onto your users. You still have that manual QA team - they're the first bunch of users in your staged rollout plan - you just don't pay them anymore and gather their feedback through bug reports. Users are used to buggy software because of other companies who do this (Google, etc) so they carry on being users anyway.