Audiobooks were once routinely sold in shortened form, with substantial portions of the text removed. Abridgement is now unusual, and the reason is almost entirely physical.
Physical formats imposed a hard limit
Audio was sold on cassettes and later on compact discs, each holding a fixed running time and each costing money to manufacture and ship.
An unabridged novel could require a dozen discs or more, producing a package that was expensive to make, awkward to display and heavy to post.
Abridging to fit a smaller set was the standard solution, and the length of the recording was determined by the container rather than by the book.
Retail space compounded the problem
Shops allocate shelf space by physical size, and a large multi-disc box occupied the room of several other products while returning one sale.
Retailers preferred compact packages, so publishers produced them, and abridged versions were often the only edition a general bookshop stocked.
Unabridged recordings existed but circulated mainly through libraries and specialist subscription services, where storage worked differently.
Those services rented rather than sold, so a bulky package could be reused many times and the cost of its size was spread across many listeners.
Digital delivery removed the constraint entirely
A downloaded or streamed file has no packaging, no manufacturing cost and no shelf, so length stopped affecting what a title costs to distribute.
Once running time was free, there was no commercial argument for removing material that listeners had never wanted removed.
Publishers moved to unabridged recording as the default, and the abridged catalogue was quietly left behind rather than deliberately withdrawn.
Listeners had always objected
Abridgement means someone other than the author decides what the book contains, and the cuts fall on description, digression and secondary material.
Readers who compared the two editions frequently found the abridged version thinner in exactly the ways that made the book worth reading.
Packaging did not always make the distinction obvious, and buyers who discovered the omission after purchase treated it as a defect rather than a format choice.
Publishers responded by labelling editions more clearly, which had the side effect of making the unabridged version look like the better product.
Where shortened audio survives
Abridgement persists in broadcast serialisation, where a fixed slot genuinely limits duration, and occasionally in editions aimed at younger listeners.
In each surviving case a real constraint remains, which confirms that the practice was always a response to limited space rather than an editorial preference.