[pdimitar]

That really depends on what does QA entail at these companies. If it's just increasing test coverage and adding integration tests then yes, devs should be doing it.

If it's just clicking UIs all day long then obviously a QA should do it. Or have an UAT environment where a few more enthusiastic customers are willing to test and report bugs.

[dickersnoodle]

It's more than that. In an org with an architecture of silo'd teams that all work on their own independent federated services, you'll need people to test out all of the variations on content, timing and error handling for the software as a whole. Depending on automated testing to handle all of that, in a live environment, is a fool's errand no matter how much it makes the development cycle seem to go faster.