The word "free" eliminates an irrational roadblock (13c is basically free but still offers a hurdle) and if one person reads something interesting as a result, then it's a win.
Also, they could box them up and offer each box off for 25c, thus offloading the responsibility of discarding the books onto individuals and preserving the notion of a library as a sanctuary for books.
The local library where I grew up tried this. It also doesn't really solve the problem of too many books. They would first put up surplus/old books for sale for a quarter or less, and twice a year would hold an event where they put the stock outside on tables and people could just take them for free. They were always left with tons of books even after all that.
It's sad to see books destroyed but they literally can't give them all away, and each building only has so much space.
Often it's not obsolete books that are destroyed, where there might be 1,000 other copies out there, but one-of-a-kind archival records:
>> The core of the book recounts Baker's attempt, in 1999, to persuade the British Library not to junk more than 2,000 bound volumes of American newspapers - the last remaining copies in the world - including a complete run of the Chicago Tribune from 1888 to 1958 and hundreds of editions of Joseph Pulitzer's ground-breaking colour broadsheet of the 1890s, the New York World.
> A researcher doesn't gain a great deal of benefit from seeing an original paper copy; in most cases, they'd prefer a digital copy. Preserving paper is inherently more expensive than preserving microfiche or digital scans.
Maybe now, but preservation isn't about now, it's about the distant future. Paper is one of the few storage mediums that has proven longevity and also requires no special reading hardware. Microfiche is probably OK (there was an article recently that stated it could lat 500 years), but I'd dispute strongly that "preserving paper is inherently more expensive than preserving ... digital scans." Digital data requires massive amounts of infrastructure to be usable (hardware, software, storage media, and reading hardware), and the rapid pace of change of that infrastructure means that enormous, continuous efforts must be made to keep it readable in the future. Seal a newspaper up in a wall and it'll still be readable in 100 years. If you stop your digital preservation efforts for that long, you've lost everything.
It's kind of the same with pictures. Most of the people I know have thousands of pictures on their phone - most of which they will never, ever look through.
But also don't neglect the long term costs of setting aside thousands of square feet, usually in an expensive metropolis, for storage.
I mean, I know as a programmer it wouldn't be a ton of effort to store a few terabytes on a local machine, make offsite backups, and write a program every 10 years to re-jigger the technology. Renting out an extra bedroom which I would fill with library shelves would be far more expensive.
Digital archives get duplicated (unless the owner jealously hides it away). Duplication is the most resistant means of longevity.
Personally, I would say even local lending libraries have a part to play in preservation. They may have copies of local periodicals that exist nowhere else. They should at least do some due diligence with other, more common, items to make sure they don't discard anything that's potentially now unique or rare (e.g. a collection of unfashionable midcentury children's books that all libraries decided to purge around the same time). Stuff like that should be kept in an out of the way warehouse or something.
A local lending library shouldn't have to keep seldom used books in easily accessible circulation, but I feel there should be other options besides that, pulping, and digitization.
How can you verify that there were no changes made during the scanning process? This is one reason I would think that a researcher would prefer a hard copy and not digital.
Sending books to be pulped is always sad, but the truth is that there are just too many books. A researcher doesn't gain a great deal of benefit from seeing an original paper copy; in most cases, they'd prefer a digital copy. Preserving paper is inherently more expensive than preserving microfiche or digital scans. Librarians love books, that's why they became librarians, but sometimes it's just not possible to justify the shelf space for something that nobody is ever likely to read.