I have also found that most TDD practitioners don't even know about generative tests (QuickCheck and similars), when these kind of tests - when well written - can catch much more subtle bugs than unit tests. Also there is a time where you should invest effort in monitoring and not in testing.
Testing with mutations is certainly interesting but I never had the opportunity to try it.
True, but in my experience this kind of testing tools do only complement testing. They should never be used to replace proper manually written tests as they are probability based and as long as the input domain is large enough it's quite viable to miss very obvious bugs not just in one rune but repeatedly.
Through if you are under time pressure it can be a good idea to, replace writing some relatively unimportant test with writing generative tests. Just only start doing so after you cover the most important parts with your manual tests.
It's kinda sad but for a lot of applications making the main features in their main use-case work right, and bringing out more main features, is more important then making all features always right but have less of them. In the end a imperfect but reasonable well working product (especially if all the small demo cases work) sells better then a perfect but very constrained product.
Testing with mutations is certainly interesting but I never had the opportunity to try it.