I always through the aesthetic was meant to evoke the sense that this was a bespoke, personalized device - i.e. it has been modified and customized to work for exactly one user.
I don't think you can have a world where mass-market technology looks like that, because why would it? Engineers with time, resources and technology would do what they do now - design for manufacturability and mass-market appeal.
That's the thing. Most cyberdecks that I've seen weren't really designed to be used as daily drivers so much as to look cool and/or be fun to build. From an ergonomic standpoint, most people are pretty well served by a standard desktop or laptop form factor; those with special needs probably would not make the same choices to serve those needs as are made by cyberdeck builders. (I'm talking the tiny, off-center displays, knobs and toggle switches on the front panel, etc.) Of course the best, coolest builds are custom; that is a mode of expression by the builder. Kinda like the next level of case modding. But even then it's not just a custom-built computer, it's one with an aesthetic sense of "the street finds its own uses for things" in a crapsack futuristic environment like the ones Gibson wrote of.
There are some really cool devices that split the difference between cyberdecks and mass-market devices; the MNT Reform and DevTerm come to mind. Sweet-looking as they are, they don't veer too far from standard laptop ergonomics, the DevTerm choosing to emulate those of the popular Tandy 100 series of portable computers.