I remember seeing this a year ago. It's a bit worrying that in that time they still haven't gotten around to building a prototype that will be as quiet as the claimed final product. While that doesn't mean it can't be done, it may point to deeper issues in the project such as yet unaddressed technical challenges or lack of funding (which might in turn suggest lack of investor conviction).
Personally I'm curious what the failure rate will look like with these things. Given it will probably be higher than existing PC cooling fans which are moving lighter loads, this may indeed be a problem.
I think what you've seen is this[1] article at extremetech.com or may be the HN post[2] inspired by that article. Both are quite interesting to read (article provided some original research in PDF, HN discussion provided some comments from the fan engineers).
Besides your question about failure rate, I'm also wondering if such a massive thing going at 2000 rpm becomes a dangerous neighbor to other stuff on the motherboard (especially in the case of failure) and to the motherboard itself. I figure the vibration this kind of fan generates may be rather noticeable.
Most larger manufacturing companies move at a glacier pace. I could see Apple making a quick decision to use these and then having them in models within a year, but few other manufacturing companies are willing to move like that.
My impression was that Apple intentionally lagged the cutting edge curve to error on stability and sound user experience. I would be very surprised to see them go in the direction of moving parts - instead I would expect them to continue in the direction of all solid state (no moving parts) as much as possible.
Personally I'm curious what the failure rate will look like with these things. Given it will probably be higher than existing PC cooling fans which are moving lighter loads, this may indeed be a problem.