IMHO, I think it's fair to say that most X10 users are, at this point, an older group (myself included) looking to keep things simple. Unless whatever controllers we've used for the last umpteen years become troublesome there's little motivation to change. My Stargate still soldiers on after 25 years with little maintenance and others are probably still mostly satisfied with what they're using. The only thing missing for me was Alexa control which is what brought me back to this forum several years ago (thank you T!). If my Stargate (and multiple spares) were no longer functional then delving into HG would be more attractive.
That said, if I were looking at a new controller, I'd want to spend my time building out the schedule and getting it operational rather than gathering and assembling the hardware and software components and I'd want minimal maintenance after that. In short, I'd probably want a packaged product ready to go rather than a 'roll my own' option. Of course, the field for that is limited for ones that still support X10 but there are at least a few left like Universal Devices, Smartenit, Home Seer and HA all of which are reasonably priced. I'm not opposed to 'rolling my own' if that's the only way to get what I want, but it's not my first choice.
So, having taken the longwinded way to answering your question, I think offering a ready to go SD card would be helpful and you'd sell a few at $20-30, but it'd be even more attractive packaged with the hardware. In essence, this is exactly what Home Seer, Smartenit and now HA are doing, all providing a cased Pi or similar with software loaded and ready to go with supported Alexa/GH integration.
Regarding pricing, for comparison there are ebay sellers offering Pi-Hole AD cards for $20 and loaded on a Pi4b for $110.