Very few of the problems Korea is facing would be solved by a shift to "a true liberal democracy", whatever that means.
I recommend Jonathan Tepperman's book "The Fix" [1]. His chapter on Korea is, in my point of view, fair, forgiving and sympathetic towards Chaebol system.
He divides the development in Korea into three periods: Dictatorial development (which I think what you call cooperation b/w private enterprise and government) 1962~1987 and democratization 1987~1997 and liberalization 1997~. I think he presents a case of what would've worked in a cheap labor export economy wouldn't work well in a post-industrial advanced economy, and how the country should move on.
[1] https://www.foreignaffairs.com/press/2016-09-20/fix-how-nati...
For example, in the 50s through the 70s, an important economic initiative was getting shoes for people. It both created jobs (making the shoes) and enabled people to get to work cheaply. Thus the gomusin was created.
It would be crazy today to have the same initiative in place. Times are different.