Let's bounce back to the original question...
In my mind, two reasons, neither should be valid.
1) Complacency. If 92% of sales of "ADV" bikes are coming from the same, stale demographic (e.g. old, white guys) as they have for a decade or longer, what incentive does that middle manager or marketing have in trying to do something different? The number above is just extracted out of thin air, but you guys are on the trails, you see who is out there riding. I see much the same thing while touring on the pavement.
2) Market Share. I can't begin to estimate the build numbers of a bike such as the one in this thread; again, I'm in the touring/street world. I have heard rumblings that the 2018 Honda Goldwing had respectable sales numbers, but perhaps not the sales numbers that corporate was hopeful for. First year of a vastly new design; some liked it, some did not.
From the front page of Adventure Rider:
There are a lot more models of ADV bike than there are 'touring' bikes. Buyers buy what they like.