It actually surprised me that Musk (or any public figure) would give up an old phone number. I would have expected a personal assistant to monitor the old number for a time until the calls/messages stopped.

Same. I’m planning on retiring an old DID for my mom.

Plan is 6 months of “this phone number is retiring, please update to _______, update your records. we’ll connect you now.”

Then 6 months of “this number is retired, hang up and call _____”.

Then 3 months of dead-end (but will review CDRs).

When I cancel it, I plan on calling any new owner to ask them to forward any calls for her to us.

Agreed. These messages are personal and are 100% intended to go to Elon Musk by the people sending them. Regardless of whether they had the wrong number or not, she doesn't have the right to go share them with NPR and the world.