The keyboard enthusiasts got to "personalized hardware" pretty early, so there might be some lessons there.
There's a whole continuum from "Buy an off the shelf unit" to "here's a barebones case you can slide ready made switches and caps into" to "mix and match custom PCBs and cases" to designing your own PCBs and/or cases. There are pretty clear pipelines and even some levels of tooling for "draw up the layout you want and get a bunch of files you can send to production houses"
Takeaway 1: A lot of this is grounded in economic realities. I did the full bespoke route (custom PCB, custom 3-D printed case) and figured it probably cost me about $500 all inclusive to get what I wanted, and that's honestly a lot of money for a keyboard.
AI won't solve any of the economic problems. They can't fix "the minimum PCB order is N units, so now you have a drawer full of spares you paid for". They can't make the expensive part you needed cheaper, especially if you're an individual buying quantity of 1/5/10 instead of an OEM buying reels and containers-full. They can't change the fact that a case for a large widget will be expensive to mill/3-D print/mould/etc.
Takeaway 2: Customers may have surprisingly limited imagination for bespoke gear. There are galleries (and even coffee-table books) full of exotic keyboards. But Micro Center is full of $50 interchangeable "tenkeyless with RGB lighting" boards; throwing on a random set of "custom" keycaps, and that's enough for a large part of the audience.
Will these customers want or benefit from more tools, or will it just give them rope to hang themselves on and give them an excuse to bail out of the purchase entirely? Even if you can provide them a gallery of vetted turnkey choices, there might be more choice paralysis than actual benefit.
Takeaway 3: Hardware is forever (relative to software). You have a lot of small firms and group-buy products that disappeared and now the owners can't get an exact replacement or repairs. Conversely, Unicomp can gut and rebuild a 1986 Model M with new innards in large part because they've been selling the same basic design since a 386DX/16 cost as much as a Toyota Tercel.
If your AI spawns a galaxy of 1-of-1 bespoke products, who services and supports them? That seems like it's only going to appeal to the enthusiast-hacker type who can keep them alive themselves, who is least likely to need AI help designing them. Design for disposability isn't a great look for anything but incredibly low-cost, limited-usecase items.