Yes, and it's extremely annoying if you want to do anything to your own car. It's bad on the same level as proprietary connectors for phones and all that, but unfortunately the amount of people improving their own cars is too low to cause any consumer feedback to manufacturers.
And I don't mean adding stupid spoilers and boost chips and sillyness, I mean stuff like adding an extra pair of high beams that can be operated with the same button as the regular high beams. That will take some serious hacking on a modern car. If car manufacturers were good at making things, this wouldn't be a huge problem, but modern cars do so many things wrong that it's infuriating. Like putting lambertian leds in places where they should have put batwing ones, forcing me to put a diffuser in front of it so that my daughter is able to sleep in her car seat. Or making it a fifteen-minute job to remove the battery for charging it during the winter, when it should take two minutes. Or putting the light that activates when you open the trunk in the far left corner of the trunk, so that it doesn't light up anything if you actually have something in the trunk. I could go on about this for a while...
An extra pair of high beams/driving lights can usually be done by just wiring a relay up to one of the lights that come on when you trigger the event you want to do; they still have to get a boatload of power to those lights somehow. It's not as elegant as pulling it from somewhere closer to the control itself, but it's very doable without too much work. The only exception I can think of for this is the HID systems that use servos to reposition the lens for high beams. Those are still fairly rare in my experience, and usually on offered on higher end vehicles that will seldom see a knife anyway. That said, I have a passion for cars and think about this kind of stuff quite a bit, so I may not be the audience you're speaking to about your complaint.
CAN has the potential to help modders actually: More and more is getting monitored by the system. If the system can be accessed by a third party device (like say via a standardized port) and the communication spec is public, the ability to do stuff with your car could be really neat. Your extra driving lights could be done elegantly, after you worked out how to get the raspberry PI to interface with the system.
Bad design lurks everywhere, it's not strictly the bailiwick of the automobile. It just happens to be one of the most common things that make it obvious.
That said, I completely agree: Some designers don't appear to actually have to use what they're designing.
