That would be counter to AI company goals. They want harness to be dumb and models to be smart so they can sell models.
https://en.wikipedia.org/wiki/Bitter_lesson
History indicates you can't tool and harness your way to effectively competing against a smarter model with more compute.
Not really. Anthropic for example sells both the harness and the models as a unified kit via Claude Code, it is in their best interest to make sure both parts work as well as possible, via reinforcement learning of previous usage as well for new model performance increases.