Indeed, most companies violate this requirement and copyright holders of GPLed code generally don't have legal/economic resources needed to enforce the license.
There is a test case that will, if successful, allow all recipients of GPLed code to sue for GPL compliance, this will open up the possibility of enforcement to users too, which could potentially lead to class action GPL lawsuits.
https://sfconservancy.org/copyleft-compliance/vizio.html
On cars, read through the presentation above, it discusses GPLv3 in cars and how that could work. Basically, there is a lot of proprietary software on top of the GPLed software in cars. When you modify the GPLed software, the other software would stop working (or be removed), and so your car would stop driving until you replaced it. You would then need to write replacements, you could then drive on your own property, or get them certified by the relevant authorities for use on public roads.
https://events19.linuxfoundation.org/wp-content/uploads/2017...