Fair points on testing, but I'll say that this isn't simple. With respect to Jeff and Tom, I don't agree with 100% of anything. At most any scale for software, it's simply impossible in any practical way to test everything. Especially when you sell software and can't conceive of the permutations in which the software might be installed and used.
That being said, certainly testing is not well done, though I'd argue it's never well done in the history of software. CICS certainly still had issues, though I bet as a percentage of code points they had less.
I haven't seen QA removed from testing as much as I've seen QA embedded into testing, which of course, is a different problem. As developers, we tend to test the happy path and look for things to function as we expect. We add "tests" (used very loosely, as this lacks engineering just as the development process lacks engineering), when we get bugs reported or problems ensue. That means we're chasing our old work, with new work coming.
AFAIK, Microsoft does write lots of tests on the SQL Server product. Hundreds of thousands of them, which are run. However these verify that code does what it should, or returns errors as it should. When we combine multiple units together, there are missing tests. There are ways in which SQL Server gets installed that people at Microsoft never anticipated. In fact, I run into people all the time with configurations that I'd never expect.
Microsoft takes the product after it's passed automated tests and there are QA people looking at other items, which further catches things, but still obviously has issues.
If you want to tell me that you manage 100% testing in some way, then you should be showing that in the last year or so you have no written any code that gets returned to you with an issue. No matter what the data, no matter how it's run.
If you can do that 100% of the time, then maybe you have teach the world about testing. However as often as I may write code that works great and isn't returned, I always find there are some items that don't perform as expected under all conditions.