With the vast amount of vehicles in GTA V, and with the ability to add more, I think that we should do something a bit different with vehicle dealerships this time around.
I'll extrude my idea into bullet points to try and get the idea across clearly.
Car dealerships would be owned by players.
Will be server owned until players purchase them.
Dealerships can be physical places, websites, or a combination of both.
Dealership owners will have a minimum and maximum price that they can display a vehicle for.
This is so that individual players not selling through a dealership will still be able to undercut dealerships to sell second hand cars to other players.
Car sales will be heavily taxed so that money still leaves the server (Required to keep our economy stable as we have money being generated and added to our econmy from other sources). Car dealership owners will only receieve a very small percentage of the actual vehicle sale.
Each car dealership will have a maximum number of vehicles that can displayed in their catalog, different for each dealership depending on size/location. It wouldn't be abnormal for a large dealership to display 100+ vehicles with the number of vehicles that we have in gta v.
Dealership owners will be able to select (within an IG UI) which vehicles they would like to display in their dealership. This can only be done once per month, but does not need to be changed if the dealership owner doesn't want to.
This will be roleplayed as the dealership owner ordering in new vehicles for the next month, and allows players to know that a vehicle that they are looking at will still be available for at least some time.
This means that players will need to browse dealerships to find a car that they like. Dealerships would try to sell the top selling cars which would be popular, this would make it so that other more obscure vehicles will become rarer as they wouldn't be seen in dealerships often. With this, it would increase the price for resales on these rarer vehicles for the second-hand market. Players will be able to roleplay with dealership business owners, requesting that the dealership orders in a vehicle they might be looking for (Each dealership would have a different waiting time depending on when they last refreshed their stock), thus creating a competing "order fee" between dealerships.
Roleplay as a whole around car dealerships and the second-hand car market will be improved by building our car dealerships and vehicle economy like this.