Yes. In-car WiFi should obviously work even if the network connection break (remember, we're talking about working without Internet, not disallowing Internet at all) - WiFi is a local wireless network protocol, not magic Internet summoner. With actual Internet connection down, it should still maintain the local network for connected devices.

As for the rest, none of those look like they should be first-party features. "Spotify on the car radio" is a third-party integration to a system that should also work off-line, e.g. for playing music off removable storage, casting from your phone (via WiFi, without Internet), or, you know, working as an actual radio. OEM maps with traffic is something hardly anyone wants anyway, because they universally suck relative to some TomTom screen, or even Google Maps.

Colloquially speaking, "In-car Wifi" has come to mean "in-car internet connectivity". I presume this is what the parent meant.

https://www.verizon.com/support/connected-car-wi-fi/

https://www.att.com/plans/in-car-wifi/

https://www.caranddriver.com/research/a32814112/cars-with-wi...

It's fine for those functions to be a casualty of the owners choice to turn off the network, just like with a phone. If automakers want to use a cellular connection in your car for non-critical functions, it should come with a legitimate user-uncontrollable off switch, just like airplane mode on a phone.

Right. We're trying to stop the world of heated seat subscriptions with a remote license verification at startup before it gets a foothold.

Right - but as the parent said, the proposed language of "all car features must keep working" isn't compatible with that.

Defining a law that allows those features to be turned off and yet disallows "data is broken, heated seats are disabled" is very difficult. After all, heated seats aren't an essential safety feature.