I've worked in enterprise software development with the full lifecycle for over 30 years.

I have found QA to be mostly unnecessary friction throughout my career, and I've never been more productive than when QA and writing tests became my responsibility.

This is usually what has happened during a release cycle.

1) Devs come up with a list of features and a timeline.

2) QA will go through the list and about 1/2 of the features will get cut because they claim they don't have time to test everything based on their timeline.

3) The cycle begins and devs will start adding features into the codebase and it's radio silence from the QA.

4) Throughout the release QA will force more features to get dropped. By the end of the release cycle, another 1/4 of the original number of features get dropped leaving about 1/4 of the original features that were planned. "It will get done in a dot release."

5) Near the end of the release, everything gets tested and a mountain of bugs come in near the deadline and everyone is forced to scramble. The deadline gets pushed back and QA pushes the blame onto the devs.

6) After everything gets resolved, the next release cycle begins.

This is at quite a few enterprise software companies that most people in Silicon Valley have heard of if you've been working for more than 10 years.