I've found a few audiobooks on Audible with narration so bad (mostly failure to properly parse sentences, putting emphasis in the wrong place) that an AI version made by random people on YouTube is superior.
For non-bestsellers, I think it'll be 100% AI narration. If human narration remains, it'll be top-tier books read by the most famous/best voice actors/narrators.
Respect your opinion but hope that's not the case.