One thing that seems needed here is how after-market additions can be added securely. There are still a bunch of 40 year old cars on the road, like this sweetie:
a little over $40 grand. At that price, you really don't care about the cost of gas. But Pontiac isn't supporting this ride with upgrades - indeed, Pontiac doesn't even exist anymore. You can get parts from after-market suppliers, but these are hardware. So who will write update code for your 40 year old 2017 sports car? How do you get that installed securely? What does this mean when it's a self driving classic car?
Right now, you have to hack the damn thing, and if you can, someone else can, too.
Great article about IoT security and the implication for durable goods.