I don't think it has anything to do with being afraid of lawsuits (or every consumer review company would be out of business) or worried about competition getting that information. They most likely get some kind of volume pricing discount (or even pricing based on experienced reliability) that is dependent on them not releasing such data.
Performance and longevity metrics are curious but they're almost useless without naming the manufacturers. To that extent, the data may as well go unpublished from a consumer's perspective on the merit that it--as you said--contains no actionable data. The Backblaze report does, and that's why I find it useful.