I think you would be hard pushed to find any big tech company which doesn't do some kind of A B testing. It's pretty much required if you want to build a great product.
Or, you could, you know, try to understand your users without experimenting on them, like countless of others have managed to do before, and still shipped "great products".
Using A/B tests to safely deploy and test bug fixes and change requests? Totally different story.
Focus groups have their place, but cannot collect nearly the same scale of information.
I don't care, at all, about the "scale of information" for the company's sake.
They are clearly good for both user satisfaction and the companies bottom line.