Or (some) western education is too unconstrained and have strayed from purpose.

Scope of gaokao = teaching the test is just teaching everything a well rounded student should know. it's not sats where you can cram a few test tactic sessions and get a few 100 extra points. At the end of the day, gaokao is there to beat knowledge floor/foundation into kids, and one would argue knowledge floor is very deep if you want to generate most bodies that can transition into technical tertiary. Like... if one want human capita pool to be launchpad for innovation, you don't make calculus optional to athletics or other extra curricular.

IMO useful perspective is PRC diaspora, who readily acknowledges they don't want their kids going through gaokao not because it's ineffective but because it's tough, and half the reason they immigrate is because their statistically mediocre kids can't hack it under gaokao, but with some east asian education rigour/pressure will still be top 5% students under western education.