I completely disagree. A lot of the data is standardized already, such as lab values and other so-called "structured" data, and can be used almost immediately without much cleaning. This is most of the routine data collection. The largest remaining part is patient notes, which are free form text but still contain plenty of useful information searchable by keyword or extractable by human curators.

You are correct that if doctors could be more strategic about how they collect info it would make the job of the data scientist much easier. This is especially true in radiology and pathology.