There are a few different kinds of updates that can be applied, each with their own protective layers.
Infotainment updates, like what happened to Rivian aren't that dangerous. You lose "convienience features" like maps, air con, etc, but generally nothing that could kill you or someone else.
Then there's system updates, which is where danger noodle things happen. Automotive manufacturers are significantly more risk averse to updating these components, and generally, if _anything_ within the system looks wonky, it's an immediate revert.
If I, as a Polestar owner, wanted to get an update for my vehicle, the nearest service center is 1.5h away. If I lived in Montana (United States), it would be realistically impossible for me to update my car. Thus, if we want to enable competition within the markets, we shouldn't have regulations that force a new manufacturer to have a global network just to add CarPlay to a screen.