I think this very fact may be part of the issue. The slides may serve multiple purposes: (1) Notes for the presenter, (2) visuals, text for the viewer, and (3)

I think this very fact may be part of the issue. The slides may serve multiple purposes: (1) Notes for the presenter, (2) visuals, text for the viewer, and (3) a document for the person who found it via Google. They thus end up being a compromise at all of them. In the ideal world, there would be three separate documents for the above, but PowerPoint is good enough at all of them that we tend to just create a single document that does all three.