And that's probably the gist of it, manufacturer find it cheaper to get rid of a legacy piece of infrastructure than "fixing the shielding" (and also support the vehicle that are already out there).
The funny thing is, some EVs like the Prius had AM radios all along. It seems like some manufacturers might be taking short cuts. I guess maybe interference regulations aren't strict enough to force the shielding issue.
Great analysis. This must be the crux of it, meaning the engineering tradeoff between good EMI mitigation and lower cost. Shielding is one way to go. I do not know the details here for cars, but in digital systems people tend to use spread spectrum clocking (SSC) to lessen the interference. Others on the thread seem to suggest the culprit is not the electronics, though, so that technique probably is not applicable.
