[salawat]

I'd hazard life critical systems requiring a greater degree of assurance that the software update actually arrived at it's destination. Maintaining connectivity to a great number of network end nodes is not a trivial endeavor, even before you get into them being able to move around.

But who am I kidding. Someone probably just pays pays for a SIM to embed in an ECU with remote wake-up to phone home and grab an update, and the cost comes from all the telco networks that need to be contracted with to forward the traffic back home.

[verall]

You also have to factor in that there's a chance of OTA failure, and the failure probably requires a mechanic visit at the manufacturer's expense.