You can't sell what you don't have! I never got, or let my kids get into the stuffed animal habit. I even had a rule for relatives' gift giving: no guns, legos, or stuffed animals. (We did get legos, but after the kids were older, and in a controlled fashion: just what was really longed for. Mostly we did Playmobil, and I was NOT having two sets of things with incredibly little pieces swirling through the house. Eldest got to do legos once he was old enough, and had the motivation, to keep them contained.) Eldest never wanted an animal, and the girls had two or three carefully selected, longed for, and loved ones. And I can't imagine selling those! Middlest still has her special friend sleep on the end of her bed!
And while I appreciate your reasoning, I am now at the point in my understanding of knowing I can't hold onto everything, that space and (paying the mortgage) have their own value. If I had the space and money, I would love to keep ALL THE BOOKS, EVER! But I don't, so no sense for me to not make the choices.
Whew. That got me articulating a few things, didn't it? I love books. I can tell that you do, too. We have always had way too many books than we have space for. There's a decluttering mantra that I was introduced to about a year and a half ago. "Inventory must conform to storage.' When I realized that that applied to books too (much as I didn't want it to!) it was a real breakthrough for me. Just another living within your means moment. You really can't have it all, but there is a value in deciding what IS important enough for you to have, and to really enjoy that. It is not necessary for me to keep every Gordon Gecko mystery we've read. It IS vital to have our Narnia books.
I guess, in a way, it is just like realizing it is not necessary to have a sandwich for lunch every day, but it is worth it to have that fantastic bread pudding when you go out for your birthday.
Oh, but how I wish I were rich enough to have a massive library. Oh, wait! I am! It is just a ten minute walk away! Yay for civilization and the tax-dollars that support it!