"just use Wi-Fi?", probably not. I don't think you'd want to create so many openings for attackers. Besides, EMI is a real issue and not something you want interfering with your critical systems too much.
To the point they are wanting to eliminate AM radio because they've gotten to the point that the uncontrollable EMI makes AM "unlistenable". So move the goal posts, and make AM radio out-of-fashion and get rid of it rather than solving the EMI issues.
1) I don't think you'll ever be able to make an electric vehicle electrically quiet enough to make AM work nicely and if you somehow did between the shielding and all the balancing currents there's no way it would be efficient. I like AM radio but these two things are probably never going to be compatible.
2) WiFi really isn't as reliable as a cable. There are all kinds of things internal and external that could cause an outage. Why bother with that when you can just run maybe a dollar of copper to the ECU?
Ignoring wifi as a poor use case here(you'd likely use something with much less interference and better latency), RF will still usually have more latency than a wire. It's more prone to interference from other random devices and even other cars. Canbus is typically shielded, which you obviously can't do with something relying on radio.
Then you have physical interference...imagine all your warning lights come on, wipers come on, and radio cuts off because your wife put her Stanley in just the wrong spot.
People don't like your comment but I have a side project that requires controlling 36 lamps in groups of 3. I rolled it over and I'm just going to slap a cheap radio on a PCB's and just daisy chain the power.
Maybe you already completed your project, maybe you already knew about Charlieplexing (https://en.wikipedia.org/wiki/Charlieplexing), maybe it doesn't apply to your case as your controller didn't support tristate output, but, just in case you didn't know about it:
It's a technique for controlling (or reading) large numbers of LEDs, switches, etc, with surprisingly little wiring. Instead of the usual X/Y of multiplexed I/O, the wiring is diagonal. To control 12 outputs (36 in groups of 3) you'd need just 4 pins (if your lamps are not LEDs, though, you probably need to put some diodes in there)
I've built my "smart home" explicitly without wifi [1] to shield against any kind of "local exterior attack" and mere communication issues due to natural phenomenon. Even for light I decide for ShellyPro 4PM to avoid wireless...
Surely without cables it's far easier, but this easiness have a price.
[1] with the exception of the car charger since I wasn't able to find a damn cabled one (it's 230Vac, not CCS eh!)
There's often the "wifi or wired" discussion around here, so I'll just add that those are not the only choices. Zwave for smart devices for example is a local wireless protocol which is completely separate from WiFi and doesn't have the same addressing / access issues.
I built everything in my house with Zigbee and could not be happier. The "everything is just a message queue" approach that Zigbee takes is fantastic for the home, and the fact that I don't have to worry about a whole complicated protocol that can do anything is great.
Aside another aspect is how to make the home impossible to live in case someone illegally occupy it (here, France, but essentially all south Europe is a relatively new but spread thing) while you are on vacation to be quicker than local authorities. Another one is avoiding connecting too much black boxes to their OEM homes.
Another final aspect is mere reliability, as a small anecdote: a neighbor due to some unknown issue have had roller shutters locked down because they have ONLY a wireless remote with a kind of ESP32 inside, all proprietary, no emergency manual opening, no access to the motor to power it directly or detach the break manually on the shutters. My home while "a bit smart" have a far little attack surface in that regard. For instance just to have central/remote lights control I've chosen a set of ShellyPro 4PM (the least expensive option of that kind I was able to find) witch operate remotely (LAN only, via HA or directly logging on the device, extended via wireguard) but i can also operate via classic mechanical switches and internally the Shelly are "dumb classic switch" + extras so if their fw crash from the physical buttons (not the one on the devices, but their normally open contacts) they still operate. For the car charger I'm obliged to go wifi (I find exactly no one domestic charging station with wired connections for control) but it's a dedicated WLAN (a small GL.iNet "stamp" size on the back of the charger, wired to a dedicated port of my homeserver on a completely separated LAN without internet access and the charger itself is MQTT/ModBUS-bridged to its local, internet-less controller/server for p.v. integration.
I can't do nothing for my car and well... Sometimes it's "app-service" to remote control A/C etc get connected to someone else car in another country and yes, I can monitor it and act on it when this happen (few times per years so far). No special hacking needed. No response from the vendor (MG/SAIC)... And for cars some demoed serious remote vulnerabilities able to physically make a car crash while running.
All those might be very rare events, but their seriousness it's relevant enough for me to avoid them as much as possible.
If my experience of trying to tether my laptop to my phone on a moving bus is any indication, I'm thinking that WiFi (as opposed to other wireless technologies) is a non-starter.
OP is heavily downvoted, but yes some ECU are moving to wireless communication although not WiFi.
It started with places where you simply can't have wires, for example tire pressure monitoring. But is now spreading to other simple ECUs. And yes, it can be jammed so obviously it's not for brakes and steering and things like that.
You can image the drivers side door has a module that senses the door switches and operates the drivers window and door locks. And communicates via RF to modules in the other three doors to control the windows and door locks.
Seriously why the heck not?
I've thought in the past what I want for trailer lights is a RF connection between the vehicle and the trailer. It can't be worse than the standard way that always fails.
