South Korea's self-reliance on weapons came straight out of vietnam war, where they were initially sending soldiers with WW2 weapons and became frustrated with the fragile American rifle that were provided, President Park directly launched Korea's own DOD (Agency for Defense Development aka ADD) which has been successful at repurposing soviet and american designs at a time where both countries were unsupportive. The K2 rifle in particular follows the same philosophy of essentially taking the grunty but reliable/rugged simplicity and then adding very economical/cost effective capacity advancements. The collapse of soviet union directly contributed to South Korea's rocket program and ballistic missile design advancement which at the time was embarassing and behind north korea ( The original hyunmoo was a repurposed american nike missile meant for air defence) You will notice the cold start process of Hyunmoo series and Russian designs are identical. Instead of repaying debt Russia sent tanks T80Us for example in return for Korean cup ramen. Lots of learning going on and South Korea ha been exceptional in particular Germany's submarine program and their unwillingness to distribute/share tech lead to Koreans adapting and successfully competing for Canada's submarine program.
Of late the Iran war showed that South Korea's anti-air as well as Biho class armor vehicles engaged drones well in UAE leading them to "we'll send you all we have now and you can pay us later" have won major trust from the region
Unlike China and Russias own weaponry which have largely been proven as duds, Korean weapons are giving American manufacturers a run for their money and if Korea can pull off the middle east region, it would not only secure oil directly while bypassing US dollar settlement, it could establish a sort of oil-for-korean-weapons and perhaps even soldiers in the near future, I think that this is the particular threat that America sees from its own ally and there will likely be some efforts to curb or limit South Korea as this article I think is starting to set the tone for.
> I think that this is the particular threat that America sees from its own ally and there will likely be some efforts to curb or limit South Korea
I disagree with that. The Korean defense manufacturers like Hanwha work hard to also build production capacity within the US and share or license IP from American firms (eg. Boramae and GE Aviation plus Lockheed Martin).
SK's industry will continue to coexist and thrive with a US partnership similar to how the Israeli defense industry built linkages with the American ecosystem (eg. Elbit).
It also helps that Korean defense companies being part of larger chaebols like Hanwha are able to link defense production contracts with other industrial deals (eg. battery and renewable tech in Hanwha's case).
I'm extrapolating here but Gulf states are very much questioning the US-Israel shield and will likely use Korean weapons acquisition to demand greater security guarantees.
I absolutely think Korea can pose a major threat to the petrodollar arrangement if left unchecked so its in the interest of US to see they not lose anymore trust with gulf states.
It's not beyond the pale to think Korea can offer significant security guarantees but I will concede that is more of a post-unification type of scenario.
But the opportunity is opening and if Korea doesn't take it, Japan might or both countries might offer what gulf states look for : being honorable and without any territorial ambitions and for both countries it might be the ultimate dream to have sovereignty over their own energy resources without petrodollar breathing down their neck since WW2