I don't see any financial gain for a commercial entity to tool up for the production of a purely X10 focussed unit you describe. Potential unit sales in my opinion wouldn't justify it. Possibly a unit that would include support for X10 but would need to include many other protocols might just succeed.
A concept like you describe would be better suited to someone operating from their home workshop and building units to order. This flexibility would allow for a more "hands on" development approach in conjunction with an already established user base in the shape of this forum's membership or similar.
Personally, I think a well speced Raspberry Pi and a decent X10 controller would more than fill the requirements of any X10 user. My personal recommendation for reliability and flexibility is the Raspberry Pi 3b+ and a CM19.
While the aim at the outset of the project was to protect potential users from the Linux command line, I was pleased to see a number of users take the plunge and as a result now have their own personally tailored setup and are already expanding their setup beyond the original ideals of the project.
If Authinx intend to pursue an idea like this I highly recommend they employ an experienced systems designer/programmer and present them with a set goals from the outset so as to avoid the mistakes made when producing the WM100. Maybe then they could look at the commercial viability of a venture like that.
In the meantime the Raspberry Pi and X10 controller combination is doing nicely thank you.