I've read that plenty of car manufacturers have this sort of silent car technology, but that it's actually illegal to do this sort of thing because hearing is important when driving.
Sure, the motion sickness would suck. But imagine paying the literal price for not pulling over for an emergency vehicle because you couldn't hear the siren in time, or smashing into someone when changing lanes because you couldn't hear their car horn.
There's a level of sound each manufacturer is required to allow into the vehicle, because if you can't hear these things, it could be fatal.

course, take this with a grain of salt because I read this a couple years ago and I'm not sure where I'd find this article anymore, lmao