> Isolated QA should not exist because anything a QA engineer can do manually can be automated.

Well, sort of maybe, but it's not always economical. For a normal web app - yeah I guess. Depends on the complexity of the software and the environment / inputs it deals with.

And then there's explorative testing, where I always found a good QA invaluable. Sure, you can also automate that to some degree. But someone who knows the software well and tries to find ways to get it to behave in unexpected ways, also valuable.

I would agree that solid development practices can handle 80% of the overall QA though, mainly regression testing. But those last 20%, well I think about those differently.

> And then there's explorative testing, where I always found a good QA invaluable.

Yes, I agree. We do this too. Findings are followed by a post-mortem-like process: - fix the problem - produce an automated test - evaluate why the feature wasn't autotested properly

> it's not always economical. For a normal web app - yeah I guess

What do you define as "normal"? I can't think of anything harder to test than a web app.

Even a seemingly trivial static HTML site with some CSS on it will already have inconsistencies across every browser and device. Even if you fix all of that (unlikely), you still haven't done your WCAG compliance, SEO, etc.

The web is probably the best example case for needing a QA team.