Building a marketplace is too hard, but building a in game system to handle any kind of asset with any kind of specification that user might wanna play with is easy?
Yep. Indie devs will spend god knows how many hours and their tight budgets building a cutting edge revolutionary tech, so amazing that will be able to render unknown items with unknown specifications on the fly. All that just for some random investment genius recoup the money that he spent buying a ugly monkey jpeg.