Yeah, this is huge. rr also has "chaos mode" to randomize things to make test failures easier to reproduce. (I understand Undo has something similar.)

I think that's one message that is completely lost in the article and in the rest of the comments here: it is possible to improve technology so that flaky tests are more debuggable.

With enough investment (hardware and OS support for low-impact always-on recording) we could make every flaky test debuggable.