I have a client that has a reverse logistics business buying second hand X, testing, cleaning, repackaging and then selling X as refurbished. They have been doing this a few years and created a multi-million dollar business unit with reasonable margins.

They did a trial about 3 years ago of buying separating, sorting, cleaning, repackaging and selling LEGO bricks/parts. After about 3 months they ended the trial deciding that the economics of the process just didn't work for them at any kind of scale.

What I just described is quite different than buying new LEGO sets, leaving them unopened and storing them for a few years and then selling them with the hope that some of them have appreciated so greatly that the overall collection is worth substantially more.