Simple. Been a QA, worked with QAs, been to conferences with QAs. We tell the boss we can't cover the whole thing, they say just cover the most important stuff. The general advice from veteran QAs is to not even say that to the boss. They know, and they can't get more resources. So veteran QAs advise others to get a feel for how much time you can spend on a thing before they start complaining that you are holding it up. Then work within that timeframe. As long as nothing major gets through it's all good. Your view is one of survivor bias. Nothing big got through, but that doesn't mean it was completely tested. Its good enough, untill it isn't. Side note, I've seen product managers close bugs, not because they weren't bugs, but because they were bad enough, compared to features they thought would sell more software. This was an outlier, usually they just wait a few years and mass close everything that is X years old. That, I have personally seen everywhere I have worked.