For instance, would you carry an iPhone the size of a shoebox if the rest of the space was a battery? Would you even be willing to carry one of the 80s phones that had a satchel?
Just the sake of conversation: Phones and cell phones are really different.
A computer can be used as work phone - during work hours, and for that is perfectly fine. And it would drastically cut back on spam calls.
At home we had landlines and that was enough to call friends to make appointments and engagements. But these were more planning and not urgent things.
If you only look at the phone/digital leash aspect - then those mini phones in the early 2000 would suffice.
If you want the distraction machine aspect, I like to read on my phone and current sizing is fine for it. And for gaming... I think a handheld is better for that.