I disagree it is fair to compare the choice to carry a HHKB (that’s Happy Hacker Keyboard for readers who are not keyboard anoraks!) with that of an Atreus. The HHKB is - at the risk of causing offence - merely a flavour of the traditional ANSI layout, whereas the Atreus belongs to a totally different family. You are therefore able to use the keyboard on any notebook computer withe few difficulties. I accept the position of some of the modifiers is different on the HHKB compared to traditional layouts. But every laptop features a reduced layout so anyone coming from a desktop setup will have to adapt a little anyway. No laptop keyboard is going to match the feel of the full travel switches on your HHKB, which I suspect has as much to do with why you chose to carry one.
As for the potential market, I reckon that an Atreus laptop will appeal to anyone using any of the split columnar staggered arrangements. This includes Ergodox and its descendants, Maltron, Kinesis Advantage, Corne / Helidox, Iris, Moonlander etc. Together, this must be a non-trivial and - thus far - effectively captive market. Keyboardio for example have themselves marketed the Atreus as a portable companion to their flagship split board.
This. Why bother with a laptop if you choose to carry another keyboard for all but the most trivial tasks. One may as well use a tablet and dispense with the unsatisfactory built-in keyboard.
Talking of unsatisfactory keyboards, here is my 12" MacBook showing how the atreus fits within the keyboard footprint. The 13.5" Framework would allow the two halves to be spread wider, enhancing the ergonomics still further.
