I think the answer is the guy who managed the project from the dealership side. Not necessarily the guy that signs the cheques.
If you're smart, you have someone on your end create a spec or RFP and get it done properly. Let's not assume dealerships are blindly throwing money at a development studio and expecting car sales in return.
Hard to assume anything in this situation. Some guys would be mad as hell, but others would understand.
I don't expect an old-school dealership with no tech knowledge to make this work, but the OP appears to be the grandson of the original owner, so chances are that he's not as traditional as every other dealer. Of course, I could be entirely wrong - I'm just trying not to assume too much here.
There aren't thousands, but there are plenty. I have a list of over 50 of them and that's not even international.
It doesn't take thousands of businesses to prove a plan has value - that's just nonsense.
Many, many things have changed in the past decade. Most significantly: reduced development time, reduced hosting costs/requirements, number of educated developers and open source web application availability.
I'm not trying to pick a fight here, but the OP's idea is not a bad idea in and of itself.
There are ways to manage it, but instead of giving advice you're assuming mismanagement (in my opinion).
