This is interesting. Beginning January 1, national parks dropped their entrance fees. However, the temple fees jumped to almost the level of the original combined fee.
This is the most surprising part for me. I didn't realize that, in 2006, when I paid 3,400 won to hike to Ulsan Bowi, around half that fee went to the temple. It does explain why the entrance at O-saek,(the hotsprings and far from any major temples) is, again, about half the Seorak-dong rate (closest to Sokcho). If I hadn't read the article, I would have figured the rate had simply dropped a few hundred won.
Some hikers aren't welcoming the (slightly) reduced entry. They don't intend to visit the temples and are upset to pay for them.