As it stands, it appears that once someone buys a 3D model, it is against the license's wording to sell 3D prints off of it. I believe the logic behind this is really an incorrect idea that the 3D artist is missing an opportunity for profit via someone else using his work to sell 3D printed models, and hence should be properly compensated for every sale of that 3D model.
That sounds like a plausible argument in theory, but in practice what happens is that, were not for the persons and businesses marketing and actually selling those 3D models, they would never have left their shelfs in the first place on websites such as CGTrader or Turbosquid. Someone needs to convince a custumer to buy the 3D prints via whatever mechanism, from physical stores, to brand recognition, to digital media in video or audio format, online advertisement, games, etc. Without this, the models you see on this website and similar ones would be forever confined to the 3D industry, and would never reach the hands of ordinary customers. That is why, in real world supply chains, manufacturers and sellers are often not the same institutions - they specialize on different levels of production all the way to reach the final customer.
Furthermore, most models are not ready for 3D printing as they are offered. Most of them need further work, often to a substantive degree, to be 3D printable. The current license, to my understanding, does not even permit this type of altered product to be sold in 3D printed format.
Everyone is losing potential income here, both 3D artists and purchasers of 3D products that intend to sell 3D prints. Yes, there are custom licenses, but contacting a seller for every single purchase gets cumbersome and slow really quick, we need a more streamlined and automated way.
The solution is simple: put a Commercial 3D Printing license checkbox on all products, with a certain percentage increase from the base price, or a fixed premium. Anyone that buys a product with that license is entitled to sell 3D printed versions of it. DAZ Studio did this already.