However the market agrees with you so I must be missing something. I used to think it was driven by media consumption on phones, and that I try to avoid, but this isn’t the first time I have heard people tout phone productivity gains from a slightly larger screen.
I wouldn't assume that.
The expression 'fat fingers' concerns the phenomena where users (including myself) lack the eyesight and finer motor skills required to type accurately on a small keyboard, so a slightly larger display makes all the difference.
Perhaps you simply have those fine motor skills (and good eye sight) so a larger device isn't necessary to prevent typos and remain productive.