I have my phone with me all of the time and it has an always on connection. My laptop has neither trait

> I must be missing something

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.

My preferred conspiracy theory is that larger, brighter screens hold attention better, so everyone involved in the whole “user experience” (phone manufacturer, application developers, advertisers, etc.) prefers (whether they consciously realize it or not!) phones to have a larger screen. Smaller phones make fewer demands; who would want to make a device like that?