There's a cost efficiency tradeoff that's always important to keep in mind. As an example, I was working with a very experienced kernel developer on a (at the time) bleeding edge mobile phone. We were seeing random memory corruption causing kernel panics. The engineer spent weeks trying to find the root cause but eventually gave up and put in a patch. You can't lose the forest for the trees - you still have product to ship & other priorities. It's rare for any bug to be so valuable to fix that it eats up all the other oxygen in the room.