To clarify on my first sentence as not sure how I can edit here :
“Kaggle competitions measure objectively a very subjective metric: model performance.”
Model performance on a metric is not Subjective I am keen to disagree. I mean if this is what the client wants (or close to what the client wants) …
You could say they only evaluate an aspect of data science that is objectively quantifiable. Otherwise you would have to calculate subjectively subjective metrics !