Visa abuse has always been a serious issue. Are you sure we have been looking the other way, or just not looking? With the latter, the crackdown we are seeing makes sense.
Most countries have a short term, productive work permit. We don't-- closest thing you can do is L-1 (and often this doesn't work: you can't hire workers for the purpose or use contractors).
Lottery based and slow systems like H-1B/H-2B don't work, and H-2B is intended for low skill labor. If we expect Korean and Taiwanese companies to establish factories, we must either provide a viable legal pathway for their technicians or accept the reality of ongoing B-1 visa violations. (I prefer the former).
(Oddly enough, ESTA/B-1 allow receiving training but not giving it).
Does this mean there is an equivalent in South Korea where the US could send workers on this Visa to receive training on how to build their (Hyundai) factories?
But sometimes you have a shorter-term need for some setup talent (especially when language skills and understanding local engineering conventions is important). This is much more common during plant construction.
I don't think you're going to quickly train US workers on how to decipher Korean documentation.