The 200,000 figure isn't super meaningful unless they report average folds to failure and standard deviation.
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.
If it's 0% failure at 200k folds, that means the 200k is about six standard deviations away from the mean, so I think (statistics gurus please correct) that says the average device will last for 1.7m folds.
Product lifetime is generally modeled using the Weibull distribution[1]. Depending on the parameters, a normal distribution is a reasonable approximation. Without data on the parameters, and just discussing whether "tested to 200,000 folds" means that every device will survive 200k folds, I think it's fair to use 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.
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.