On the contrary unfortunately, it's all secret for the average consumer. People that never worked in the industry greatly underestimate how much it really cost

On the contrary unfortunately, it's all secret for the average consumer. People that never worked in the industry greatly underestimate how much it really costs in R&D and production to make a car. Adding "authentication" and "encryption" in this environment is way more complex and has more implications than importing yet another library in a web app. Even so a few manufacturers go to a great deal of effort to secure their stuff while others are using 20y old architecture because it works and it saves money. I want to say that "premium" brands are much better, but there are a lot of exceptions. However cars with lower margins and lower overall cost will be worse.