(which is some sort of regulatory problem probably, the point is that it is the status quo for there to be a dealership oligopoly in many areas)
It's not really super convenient to get service 60 miles away.
Worse, Tesla is effectively a a national monopoly. And that's far worse, because it has no competition for sales of Tesla vehicles or service.
The manufacturer might like to claim the entire savings, but there are two reasons that typically wouldn't happen.
First, then the manufacturer's margins are higher, which changes the calculation of how much margin to sacrifice to increase sales volume. If before the manufacturer was making $2000/car and the dealer was making $2000/car then the manufacturer lowering the price by $1500/car to double their sales isn't profitable; double $500 isn't more than $2000. If the manufacturer is now making $4000/car by cutting out the dealership, lowering the price by $1500/car to double their sales is worth it; double $2500 is more than $4000.
And then second, because the competing manufacturers would have the same incentives under the same circumstances. If they lower their prices by $1500 to double their sales, that's coming at your expense if you don't do the same.
According to this [1], new car dealerships have a profit margin of 1-2% while auto manufacturers have a profit margin of ~10%. Anecdotally, some dealerships have no profit on vehicles, and rely on services contracts to drive profit.
I interpret this to mean that there is significantly more competition between dealerships than auto-manufacturers. If a consumer wants a specific brand, they can choose between dealers and often will travel long distances to get the best price. When a dealer buys a brand, there is a single supplier with global monopoly.
I think the disproportionate share of profit already going to manufacturers also undermines your argument on the trade-off between sales volume and splitting of profit.
You'll often see this when selling used stuff in America. Poor people will haggle to the end of time because every dollar matters to them - something that manifests in selling something at a higher price being more risk-free than selling something at a lower price. For the same reason, if anything goes wrong with the used product they will be upset with you. Because every dollar counts to them.
I throw away cheap stuff instead of Craigslisting it because of the danger of it only being worth buying to poor people.
By the way, Americans prefer calling it 'negotiating'. You 'negotiate' a lower price, you don't haggle things down to a lower price.
In line with the above, private sellers are generally amenable to haggling because it doesn't matter that it doesn't scale. So when buying a used anything on Kijiji, haggling is expected, particularly if it says "OBO" (or best offer), but not if it says "firm".
If the price is set semi-arbitrarily at the time of purchase, like some U-pick auto junkyards, the person setting the price is right there anyway, so haggling may be acceptable.
I haven't researched any of this; this is just my intuition from experience.
Anyway, being able to advertise a price as firm does provide a convenient escape hatch in that scenario.
They're baking in a fixed profit on used inventory and the customer has no option to impact their profitability and reduce acquisition cost. Now that I think about it, I am going to buy long terms puts on their stock,as this event should completely destroy their business.
Consider every dealership horror story you've ever heard. Both from customers -and- floor employees.
In both cases, having all dealerships across the country owned by the MFG means there's larger pools of workers to unionize, and a greater risk for a class action.