That's right. This already is happening. I got bored of waiting for "Linux smartphone" and accidentally found that it's actually quite easy and affordable to build a wearable computer from scratch. And I built myself one of course. https://www.google.com/amp/s/www.theverge.com/platform/amp/c...

I just used new generation of the same display, and a one handed Twiddler 3 keyboard.

Raspberry pi doesn't have cellular, so I am looking at Zero phone project which has a solution. But so far I am already extracting value from my wearable computer in many easily implementable use cases.