It's not how they were engineered it's their parts supplier, which is usually the case.
Actually, it's often both.
BMW tends to engineer things with very tight tolerances, which is one way they continue to push the features/performance/price/weight envelope.
Some suppliers seem to have difficulty manufacturing these parts in great quantities under BMW's tight specs. So marginal parts sneak through and get put on shipping bikes, allowing random failures to occur on random bikes at random times.
Now that falls on the suppliers, but it also falls on BMW's engineering and quality control departments.
And what usually (eventually) comes out of such failure analysis is a combination of BMW reengineering the parts to allow for wider manufacturing tolerances, and BMW taking tighter control of the quality/testing phase. And in some cases, changing suppliers outright.
That explains the recent switch failures (redesigned internal ribbon cables), the RT recall (redesigned shock components), the slew of final drive failures (several redesigns to reduce and then eliminate tight preload tolerances and marginal seals), and many of BMW's other failures.
The frustrating thing is that this still happens on brand-new BMW models, even though its been getting better overall (My GTL has had fewer issues than my K12GT, which had fewer than my LT).
But that's the price we pay for bleeding-edge technology. For some, the hassle is worth it and the pain disappears as soon as you roll on that throttle. And for others, it isn't, so they sell off and move to another brand.
Where you may fall into that spectrum is entirely up to you . . .