A podcast requires thousands of pieces of fragile infrastructure between the sender and receiver.

Radio can send signals between continents with zero infrastructure between the sender and receiver.

AM is critical for emergency scenarios. When Hurricane Maria hit Puerto Rico, all our infrastructure was completely devastated.

The only way to receive news or bulletins for weeks was just one remaining AM radio station that kept broadcasting even as the storm hit and their building began to flood.

>why is the medium relevant at all? what does radio do that a podcast cant

Deliver the news to you anywhere and everywhere with a receiver that can be built from scavenged garbage. Terrestrial absolutely still has a place, and will most likely outlive the internet.

AM radio, like other frequencies in the low HF spectrum, travel using ground waves then ionospheric refraction during night which can let the receiver pick stations several thousands of Km away. FM and generally VHF frequencies require mostly the transmitter to be in line of sight. When a disaster occur, you can pick AM radio emergency transmission from behind a mountain or from much far away than a FM station. This allows the elimination of any dependency on repeaters which are a weak link, especially in less than free countries that censor radio transmissions, whose listener couldn't pick a station from another country if it needed a repeater in theirs. AM is for freedom, not for music.

In an emergency situation, you can build a CW transmitter off parts reclaimed from a broken PC power supply, connect a diy antenna made with a simple wire and be picked up from another country; a walkie talkie will stop at the 1st hill.

Radio has an almost orthogonally inverse set of failure modes than internet streaming.

Internet.connection (∴ tracking) not required

It's not just the medium. Streaming from the internet is a totally different product than radio. There's no reason we can't have both.

AM signals have a far reach and are often used for road and emergency updates.

Work without internet infrastructure

Emergency broadcast is a big one, as well as location-specific information like road conditions.

Count how many subscriptions are between you and that podcast.

They live in different layers of "medium". This is like asking "What does piping do that juice doesn't?", they're not mutually exclusive.

what does a movie theater screen do that a phone screen can’t?

It's literally absurdity that you even wrote this at all.

work without the internet/power