That said, it's very easy to remove Audible DRM. Each of your purchases is encrypted with the same short series of bytes. You can fetch them by uploading any purchase to this site [0] (also open source). Then, FFmpeg supports the `-activation_bytes` arg for this exact purpose:
ffmpeg -activation_bytes <ActivationBytes> -i <Input>.aax -c copy <Output>.m4b
Alternatively, Libation [1] is a great open source app that simplifies this process. It's a little rough around the edges, but it gets the job done!I know this is correct because I found out the hard way. Couldn't keep up with listening so cancelled the sub. Came back when I had time but the credits were gone (think about 7). Was pretty mad but found out they do mention this somewhere. Threw 5 euros at Libation, downloaded my library and never looked back.
Audiobooks from Audible can be downloaded via the UI. They will have DRM, but it's possible to remove.
If you have audiobook files without DRM you can listen to them via any app that plays audio, but there's also at least one OSS project that aims to fill audiobook UI niche [1].
Cancel your subscription, download all your books from audible, put them on a NAS, run Plex, and use Plexamp for access.
I still buy things via Audible, I just immediately download them and load them into my Plex server.