I think the discussion here is missing something. The issue isn't "shielding" the radio. Modern power electronics, including Hybrid/EV drivetrains and modern electronic transmissions, produce in-band interference for broadcast AM. If you shield the radio, you're blocking the _signal_, as well as the noise. The only solution is to shield the power system (including the drive motor). This can add significant cost in both engineering and production, and interfere with thermal management (gaps let out hot air and RF!). Of course, with enough effort, anything can be shielded, but most EMI emissions masks I work with only go down to 30Mhz! Single MHz is below the range of "RF" and within the range of "Power Electronics" in the minds of modern engineers.

The real issue here is that while FM made the switch to hybrid Analog+Digital, AM is still living in the past. The technology has not changed in literally a century. The FCC has authorized hybrid AM operation, but there hasn't been any real adoption. We have 100 years of signal processing magic, and it would be so much cheaper for car manufacturers to include a single chip than to properly shield drivetrains just for AM radio backwards compatibility.

We should have spread-spectrum orthogonal-multiplexed radio beamed to the entire country from space. 100 geo-coded channels, and your car automatically plays the one for the region you're in. Adapt or die, but the high power future isn't going to wait up for AM.