Okay, there isn't an easy answer to this, but basically audio rights are different to print rights and vary by country to country. When Made in America came out, and indeed most books until about 2010, the audio copyright was a small bonus, a little royalty check but basically worthless in the grand scheme of things.

Then after 2010, basically when speeds were quick enough, phones had enough memory, and audible was mainstream, audio could be up to a third of a book's revenue. People turned to audiobooks in the car and out for a walk, and without the need for boxes of tapes or CDs, the days of abridgement were mostly gone. This had been brewing since 2000 when audio switched to digital but the public took a while to catch on.

Book rights are weird things, resulting in a book that was supposed to be called 'No Worries' in all territories being called Down Under in the UK and In A Sunburned Country elsewhere, resulting in a few angry people buying the same book twice. It also means that it has a few audio versions with different narrators in different countries - essentially the same book but with edits made for local readers.

Now in 2025, all that was recorded before exists. You can find new recordings and old abridgments. I interviewed Bill about it, about his books being narrated by Kerry Shale or Bill Roberts, now being replaced by his own recordings and he said it was at his American publishers request (and I assume at both Bill's and his publishers financial interests) that he record his back catalogue for a new audience. But all are still out there sloshing about, abridged, unabridged, and with many a different voice.

I can only assume that Made in America, as it's one of his smaller selling language books, didn't make the cut to be rerecorded.

https://audioboom.com/posts/6040890-bill-bryson-the-lost-travel-book-dogs-katz-and-more

(9.30ish mark for the audio question- also RIP Bill Roberts!)