This has been bugging me for a while. I've always had penknives/pocket knives (Swiss Army knives), and even the cheap ones are made of stainless steel. They include screwdrivers and other similar tools to bike multitools. But my bike multitools tend to rust, badly, if they get wet (and they do get wet, as I ride in all weathers in a wet country). The only stainless ones I've got are small and effectively incomplete, though I see that Lezyne make one and possibly Topeak (or maybe that's just the body)
So is there a good (engineering) reason why bike multitools are rarely stainless?