I don't think it's reasonable to judge Conventional Commits on something it doesn't claim to do.

I can't see any suggestion on the CC site [^1] that it "solve[s] the core issue of the poor commit messages problem."

Rather, it's explicitly described as "a specification for adding human and machine readable meaning to commit messages."

I'd say it accomplishes that modest goal.

[^1]: https://www.conventionalcommits.org/en/v1.0.0/