If I'm a lego trader and I buy your set for $900 hoping to sell it later for $1000, in the meantime that's $900 I can't invest in anything else. And maybe I guessed the set's value wrong and I end up unloading it for $800, taking a loss.
On the other hand, if I agree to sell that same set on consignment? Zero capital outlay, zero risk of me taking a loss - just some shelf space and admin work.
Unless the store owns its building and has too little inventory to cover the shelves, the cost of not filling the shelves with the right goods is quite serious. In a low-margin business like retail, "just some shelf space" reads almost like "just some gold bars".
Stores also wanted to look full. We actually had parameters in our inventory management logic to increase inventory just for presentation reasons. If inventory is expensive, having some free, quality inventory can be valuable in and of itself even if it moves slowly.
Most of our business is selling low-price, entry-level products. There's a 80-20 distribution of people getting into the hobby versus people upgrading after a couple years. Consequently most of our floor space and inventory is devoted to high margin, quick turnover, entry-level products.
In my experience the floor space is less of an issue for high end products than the capital expenditure to bring in the inventory. On the consignment side we only take products aimed at the remaining 20%. These are specialty items we wouldn't have in regular stock. It's a win-win because we don't have to deploy capital to bring the product in-store, but we do have space to showcase some higher end used product.
I know this from a few friends who are deep into tabletop and boardgames, and they would regularly work with the one or two small stores around to get some special, expensive item (to help keep the shop afloat).
The annoying thing is people with lots of money and no experience who want the special expensive thing but they want it now and they don't know what options they want. I'm sure other fields are good at separating fools and their money but niche hobby retail isn't the Audi dealership, we're not just trying to upsell you for fun.
However, in this particular case, the legos were initially displayed as a customer attraction, and then kept in storage. Presumably there's still some inventory cost in storage, but the shelves are clear.
>> The collection will be on display in the store's party room from 10am till 6pm on Saturday, November 11th, and 11am till 6pm on Sunday. The collection will be available for sale immediately, so the best time for pictures will be Saturday morning. The collection will not be stored on-site after hours for security reasons, and after Sunday the sets will be available for purchase but stored elsewhere.
But instead of costs = (product purchase + shelf space), the costs are only (self space).
So "just some shelf space" is correct in fact and implication.