Agreed - I think Ineos missed the mark on not only the size of the US market, but the owner profile. The Grenadier at $80k average lands squarely in the US upper middle class - 40-50 million consumers according to a quick google.
That said, I don't think the US dealer network can afford to scale geographically in the short term. I think it only makes financial sense to focus Grenadier dealerships on high population, high income areas. The good news is this will likely sort itself out naturally, dealerships without sufficient buyers and service within a normal range won't be able to stay in business.
For example, I really question the longevity of RDS in Philadelphia. Now that there is coverage for the DC Metro, a 2 xNJ, NY and CT... Who's driving all the way to Philly? It'd probably be more logical to put a second dealer on the south side of the DC Beltway.
Which begs the question " How do you increase sales in areas outside reasonable distances from a dealer?"
Answer: Owner service reset ability, a scan tool, and a workshop manual.
Most of the real problems have been sorted with a few outliers like the front driveshaft or whiny steering boxes, etc. There may be a few other things that will pop up over the years but I can't imagine what that will be as the parts used in this these vehicles are pretty solid. That means Ineos playing everything so close to the vest is becoming inappropriate. Most buyers will have the dealer perform every repair while under warranty and a sizable portion of those will continue to do so long after the warranty has expired but not if you live a day's drive away - or use one far away from a dealership network. The various resets requiring dealer input reveals just how uncertain they were after entering this entirely new field with an entirely new product.
Providing a manual may have seemed at some point like cutting their own throat but It will need to happen. A readily available workshop manual will prove that the Grenadier is the rightful heir to the OD/LC70 thrones, drive consumer confidence with both the hardcore users and the wannabes, and promote sales both within and outside of the shrinking dealer loci. Which would they rather have? Full service bays by milking every penny out of their current owners or full service bays and full pockets from higher sales?