[moralestapia]

I think it's mostly a framing situation.

Two big things that are different:

As an adult, many of the books one buys is to keep them. There's even that saying "He who lends a book is an ..."; working against you. In contrast, most of your children books you get rid of them, garage sale, give them away, whatever. Save for a few of them that become special, most are pretty much disposable.

As an adult, buying books is not a pressing situation, sure there's a lot of those you'd want to buy but you can easily put that for later, even forget about it. Take a kid into a bookstore and they want all the books, and they want them at that moment. So, it is more of a pressing issue to keep your kids busy with new books all the time.

PS: If you need a partner on this, I'd be up for it! My daughter is past the stage of kid books now but I wouldn't mind building it for the benefit of other kids.