It must be something that is either more portable, more useful or both, like a watch or vr goggles or a holographic projector. Or is a slab of metal with a glass display the ultimate form factor?
A desktop with fiber internet, multiple large high dpi displays is the ultimate form factor.
Smartphones are useful for ordering dinner on the go, checking traffic, taking a picture, and making actual phone calls. If you use it for anything more than that, it will warp your personality in a bad way.
Given unlimited potential, no, it's not. Given our current constraints in terms of energy density and electronics size, yes, it probably is.
In an unlimited potential world, it would be great to have a phone that was like an A0 sheet of paper folded into an A7 or A8 sheet. So you could "unfold" your phone several times to get a display ranging from a standard cell phone up to a meter across display. No more conference room TVs, someone will just unfold their phone and hang it up.
In a far more advanced world, I expect some kind of human-machine interface will crop up. The twist I expect is that I think they'll be genetically engineered, a la CRISPR. Rather than cutting people open and putting metal inside, they'll inject you with a virus or something that leverages your body's existing systems to make your body build that feature itself.
I.e. if you want that human - computer interlink, they give you a virus that causes your body to deposit iron inside your ears in the shape of an antenna and causes the growth of new nerve tissue to convert those into nerve signals to the brain and maybe a new part of the brain that can "decode" the new nerve signals.
We know that people will sacrifice power and medium-term convenience for portability and always on connections that work in the real world, so if we maximize those:
I am thinking of an Apple glass with AR holographic display that is hooked up to a controller you can keep in your pocket for when you can't use Siri as much closer to the ultimate interface. You want access to all the information, but at the same time have your hands free and the privacy required when you are out and about.
Eventually there will be a direct neural interface to your pocket terminal with POTS compatibility and you won't need either voice Siri on a hand based input.
Phones are now powerful enough for general computing tasks.
I would love to be able to carry my phone anywhere, hook into an available monitor/keyboard/mouse "dock"/dongle/kiosk[1], ala the Motorola Atrix 2[2], and use it as a general purpose computer.
1. Assuming the skimming and other security vulnerabilities could be addressed.
Smartphone does a few things: identity, communications, and computing. If there were a secure protocol for identity and ambient communications/computing. I guess smartphone could be replaced for most day to day things.
I'm imagining something closer to Star Trek (though we're pretty close now)
Combo of watch, AR/HUD glasses and hyper intelligent earbuds could cover “needs” as well but I’m not sure any of those form factors can do what a phone does so well alone.
I’d say this. Eventually the computing power should fit in a watch that can project to AR glasses. It’s shocking how often I forget where my phone is around the house. Wearables are the key going forward.
Phones have only become bigger, while smart watches exist and definitely didn’t replace smartphones. Hour is an information that fits on your wrist. Everything else needs a bigger display…
And FWIW, I personally ditched the wristwatch when I got the hour on my phone.
Seems to me that an implant would be the next step forward. Not everyone would go for it but a big percent of the population would go for it in a snap.
Smartphones are useful for ordering dinner on the go, checking traffic, taking a picture, and making actual phone calls. If you use it for anything more than that, it will warp your personality in a bad way.