This is illustrative of the continuing US mentality that getting the most sophisticated tech for its own sake will still ensure US dominance. This obsession with more and more strategic bombers and drones reflects the present doctrine of carpet bombing cities into smithereens, which had only worked with the likes of Iraq and Afghanistan that have no air superiority whatsoever. And which will prove to be a disservice to the US in the event of a hot war with its adversaries (assuming that the ongoing Ukrainian War is considered a proxy war against Russia). But even in the case of Afghanistan, we see clearly how America eventually lost to a non-state actor having nothing more than small arms and IEDs and making do with asymmetric warfare.
On another angle, Russia doesn't see any incentive to develop the latest-gen stealth bomber (even if otherwise they would have the resources and know-how) because their doctrine consists of pulverizing the enemy with tactical air and artillery support, preserving the infrastructure of occupied territory, and grinding down the enemy in a war of attrition from entrenched positions. All of which are working wonders for them in the Donbass and at the same time resulting in a net financial gain in the long run. And as I said before, the Ukrainian War is proof that infantry + armor support + artillery will remain the most important element in combat for the foreseeable future.
I'm not questioning South Korea's industrial capacity (I'm rather impressed with this development), but rather their geopolitical motivations. They're trying so hard to punch above their weight class as a middle power country that it might backfire on them and result in bringing down China and Russia's combined wrath upon themselves. What many outsiders don't know is that China had sanctioned South Korea in 2017 over the possible installation of US-made THAAD missile defense system (similar in appearance to HIMARS) and it had hurt the ROK economy. South Korea is making a risk meddling in Eastern European affairs trying to further their own interests.
South Korea has for the most part had amicable relations with Russia - once again, as is the case with Israel, Russia has leverage with South Korea, as they could offer modern armaments for sale to North Korea - or worse - the designs for North Korea to produce Russian arms at a cheaper cost.
Russia can itself employee the American strategy of bombing out a nation with limited air defenses (it possesses large quantities of unsophisticated bombers).
Also, it is inaccurate to say Russia has a strategy of preserving the infrastructure - early on in the war, Melitopol, Kherson, and some other places may have been taken undamaged, but look at Mariupol and Severdonetsk.
The problem with the American war industry is that the military manufacturers have too much power and are bent on making expensive sales as opposed to practicality. I know socialism is not big on this forum, but Russia's state owned armaments industry is quite efficient at producing cheap, durable, and useful equipment. Also, Russian and Chinese engineers make at most half of what Americans make, so obviously it is cheaper for them to produce arms. The Russian goverment gets a very good cost per value out of it's arms industry. The majority of Russia's equipment issues have been with poor maintnance and corruption in the millitary, but their equipment is known to be very good for the price.
In this case the free market arms industry is not as efficient as a state command system, because the seller has control of the buyer (through "legal corruotion" - lobbying) - blinding the buyer (USA government) from making the best choices.
Better to the point - the US millitary bought helicopters from the Russians to give to the now deposed Afghan government rather than provide an American made offering.