I respectfully disagree with you. There is a reason that BMW, FIAT, and Land rover and don't have the greatest reliability. Yes it's true they don't have the greatest engineering, but it's also because they haven't perfected manufacturing. Toyota famously implemented systems like Kiazen, and are constantly improving there cars, involving their manufacturing staff, their mechanics, everyone to perfect there reliability. That's why I really hope Apple doesn't partner with BMWs, Chryslers (although Chrysler has been improving), or other brands that aren't committed to quality.
I understand what you're saying. Basically that no matter how much supervision Apple provides, that a manufacturer may simply be incapable of manufacturing a quality product. I agree with you that this is a possibility.
However, I have a counterpoint to it. In addition to my original point that Apple takes close control of the process and applies their own QC which would help to prevent problems in the first place, Apple has also shown a willingness to
completely walk away when the results are not to their satisfaction.
For example their partnership with GT Advanced Technologies where they had big plans for sapphire screens, a partnership with the Governor, announcement of US jobs, worked a deal with the Federal government for special customs zoning, powering the plant with 100% renewable energy, and on and on. But after all that, when GT couldn't deliver to their specs, Apple dropped it and moved on.
That's the most famous and dramatic example, but fellow long-time MR readers know this has happened on numerous occasions.
I guess my point here is that history shows that Apple is aware of the possibility of being let down, works that into their contracts and plans, and has shown the willingness to dump partners that can't deliver on their promises.
I think Apple would rather walk away during the initial testing process and move to another candidate, rather than to green light mass production for piles of crap.
In any case, time will tell. This is all conjecture of course because we don't even know who they'll pick. Anything could happen. Heck, they could pick a truly world class manufacturer but then completely fail on the design/engineering side.