I tend to be optimistic and hope that the theta problems have been resolved, but maybe after spending a huge amount of money replacing engines, Hyundai decided to roll out the knock sensor ECU upgrade to detect premature engine failure as a risk mitigation for all cars with those engines just in case there are some latent issues. If they catch a few engines early and can fix it with bearings instead of replacing the entire engine, it’s probably a huge net savings.
My experience with risk management is that the low likelihood/high consequence area of the risk matrix is a terrible place to be. Take an extreme example that there’s a 1 in 1 million chance that an asteroid is on a collision to destroy all life on earth but it will take a trillion dollars to mitigate by redirecting it. What do you do? Spend a trillion bucks and have it miss anyway and your decision will look terrible. Spend nothing and the asteroid misses and you’ve “saved“ $1 trillion. You‘ve got 1 in 1 million odds of being a hero with a successful diversion. (On the plus side, spend nothing and get hit then there’s nobody around to criticize your decision, except maybe your spouse will have a few choice words for you .)
Making up some numbers, Hyundai might have thought along the lines that it will cost $40 to add to every car, but it might cost $6000 to replace an engine, so that’s allowing 1 failure for every 150 cars to break even, which would still be too many engine failures. But they have a bigger incentive: customer loyalty. We want reliable cars and if there’s a problem, quick fixes are preferable to timely engine replacements.