It is an actual case, a plenty of people want to buy an artwork but they don't want an actual piece in their possession - sometimes they want to just hold it for investment purposes, and sometimes they don't have the space yet, but they expect to have it sooner or later.

That's why you have storage houses for artworks, and artists often sell their artworks to collectors but keep it in possession for years. Also people own artworks but "rent out" to galleries - which makes it a win-win, and a free storage for them :)