[0] https://www.anandtech.com/show/14136/samsung-galaxy-fold-can...
From that article, it could be that they test to 200,000 folds because at that point 99.6% have failed, and the 50% failure rate might be at 100,000. Or 20,000. Or 190,000.
I don't think they're saying that 100% of phones will last to 200,000 folds. That would be a bold claim indeed.
You’re also assuming a normal distribution. This very well might not be a normal distribution
Agreed that they probably expect some percentage of RMAs. In fact, I'd argue that "tested to 200k folds" means that 200k gets them enough failures to model the lifetime distribution, so the average lifetime is probably considerably less than 200k.
This guy independently tested a Flip 3, having people manually open and close the phone rather than using a machine, and it lasted 418,500 cycles before the hinge broke.
I'm sorry, but I don't trust anyone claiming they've solved it until they've proven after 2 or 3 gens that there are no elevated failure rates.
Maybe this Google phablet will be the first that solved it, but I can't press X any harder for doubt.