Assuming it evens out (big assumption) it’s still a dumb concept. The entire discipline of materials QA exists to eliminate this type of randomness. Hey, will that 747 crash this trip? Dunno. We got a bad roll on the aluminum so had to stuff a bunch of extra aluminum in there. Hope it holds up.
I generally defend the engg system, but rng in engineering is an oxymoron.
Well, you have to remember that engineering is going well past ordinary QA for any kind of manufacturing. The simple act of going into engineering is going beyond what a quality assurance team can produce in any real quantity, not to mention how the engineers are employing concepts and techniques that even the manufacturers themselves aren't particularly aware of. Once you are dealing with things several Sigma from the norm, RNG is the name of the game.
It's similar to overclocking computer processors. There's countless limiting factors that all need to be eliminated if you want to have the greatest possible results, and even after all peripheral factors are accounted for there's a good reason why its referred to as "playing the silicon lottery".
As another example, did you know that a plain silica glass rod 10mm in diameter can potentially hold in the region of 100 tonnes in tension? No architect in the world would ever consider a structure using such a rod, though, as even a decently made rod of those dimensions can generally only hold about a tonne before breaking in practice and once you account for safety and reliability they'll probably go for a fraction of even that. However, it is theoretically possible to create such a glass support rod, and it's the realm of ED's engineers to attempt to take advantage of that potential performance.
If anything, the old engineering system made far more sense in terms of RNG, as it involved replacing components, testing and repeating ad nauseam until desired specs were reached and progress wasn't guaranteed as it was possible that the replacement wasn't as good. You replace some capacitors with other ones of the same design, and due to microscopic differences in internal structure they come out with slightly different properties; you replace a structural beam with one of the same composite, yet those tiny manufacturing tolerances means that it doesn't quite work the same way.