Is QA valueable in Software Industry?

I’ve worked at two companies with different culture, pov pm

1. Company A- don’t believe in qa. Pms should test their features.
2. Company B- Without Qa approval no release happens.

Both the companies have million plus users on app.

What I’ve seen: Company A always run into trouble. On call devs have huge amount of responsibility. WhatsApp group with execs who point out bugs and downtime; all day and all night. Dysfunctional system, most of the folks always under stres.

Company B did really well. Most of the comms happened on slack. No stress and enggs and pms had great wlb.

Now both the companies hire quality engineers and Ems. What happened in case of A was more like PMs ended up testing happy flows (pls note we’ve lot of other work), with little to no documentation.

Ideally, if the company has resources, then it’s always good to have qa team, not only to test current stuff out but also to check for backward compatibility.

QAs should not be part of every product. Developers should write unit test cases, take ownership of their work and ensure shipping quality code and testing the features end to end. QAs are needed for different things. And developer shouldn't depend on QA to find out and test the edge cases. It is shifting responsibility , delaying feature delivery by letting the QA test, then fix bugs, then again testing. This should not be there. QAs are good in their work, they deserve respect and good pay. But they should be at a later stage and not the only one testing the features thoroughly