As a fun example, I’ve been simulating core memory at the level of electric/magnetic fields lately. It takes literally trillions of floating point operations to simulate just 1 nanosecond of a single bit of core memory. In doing this, I can identify things like “if we were to arrange the cores like <this>, we could reduce the peak magnitude of the radiated fields when a core flips, thus we could get by with using slightly softer ferrites (which use less energy when switching state) without encountering noise problems.”

But of course, a trillion fp operations was a lot more back then! Having more advanced tech made it substantially easier to optimize the earlier tech. Optimizing compilers are maybe a more direct, but limited, example of this. The faster a CPU can run your code, the more cycles you can have your compiler spend making that code run even faster. I’m not sure there’s a good term for these “mutual feedback loops”, but they seem to pop up a lot.

Really, what nukes the repairability of a lot of products these days (ignoring the repair-hostile practices of many companies) is the cost of the item vs the time needed to disassemble the unit, track down where something went wrong, repair it, reassemble, and hope that component didn't blow because something else upstream is faulty that you didn't find. Cuba and Africa the time is cheap while replacement units are somewhere between expensive and unobtainium, USA/Japan/Europe not so much.

I hear that all the time. Usually, in the same paragraph, they'll also ask for Feature X, Y and Z.