What is this opinion based on? Is South Korea known for their engineering?
Has any equipment really evolved much since the Hammer Strength line?
I can't speak on their engineering for fitness equipment but I can tell you that overall their health/fitness/gym selections are the best I have ever seen in all my interanational travels. The average hotel gym is on par with a small size UFit or Planet Fitness. The hotel I stay in as a general fitness area with a ton of machines and then an upstairs level with tons of free weights, power cages, deadlift platforms, etc. and this is a hotel. You see healthy fit people all around. Gyms are very reasonable. $15-25 a month and super competitive. There are some nice extras to attract people into choosing them over others. Indoor golf driving range, cyro units, etc
By comparison:
Paris where I am, historic area - no gyms. Hotels - no gyms. Outer areas you can find ok chains. Keep Cool and Basic Fit being the most common. Note the actual "gym" part is called the "musculation" area.
Japan - from last month. Overall a fit society due to dietary habits and walking every where. They have common gyms. Golds, 24 Hour Fitness, GOAT, the last two offer day passes for about $20-30 per day. Facilities are on the small side. Membership is expensive. $70-90 per month. This is because not many people go to gyms and rent is high for the small spaces. But the people who are gym members are serious. You won't find kids hanging out or instagrams being made in them.
Hotels rarely have gyms. If you do find one it is either a basic universal multi station machine or dumbells. And a couple of cardio pieces. But very very rarely treadmills. They have bikes and epilitcals. But very seldom treadmills because people walk every where.
Brazil - the biggest "gyms" are usually BJJ places with the equipment off to the sides. But you can find more serious gyms away from popular areas.
Bangkok / Chiang Mai - you have small serious gyms comparable to golds on one end, massive Moo Thai (ha) centers with some equipment on the opposite end of the spectrum. In the middle is medium size with about a 60/40 split for one the interests.
In short I would suspect Korea had better made engineering just based on the factors above and the types of crowds / gym members that they attract.
