My guess is because 3d printing is becoming an increasingly popular hobby. Especially with folks who enjoy role playing games and for sci-fi fans.Indeed if you look at kickstarter, some mesh creators have raised megabucks. 

Which is why your point here is rather interesting. I can see how an extended term would be fair enough for games, because someone might be able to extract the mesh from the game, thus depriving the creator. But I wonder why should buyers have to pay more to print their purchase when compared to rendering?

OK sure that term is common to many stores, not just the marketplace here. But it feels kinda counter creative to getting sales. It's a bit like Daler Rowney telling paint brushes buyers they can't use oils, only water-colours.

It's the same when you see extended licences limiting the number of times something can be printed. Most licences don't define the number of times we are allowed to render a purchase.I could also make a render and sell numerous copies as an art print, yet I don't have to cut the creator into that profit. So it's not like a creator is losing out on anything.

Yes we might get a short term gain by selling an extended licence. But I wonder long term are we doing ourselves a disservice with extendeds? Higher prices are less likely to make people buy. Plus overly restrictive terms are more likely to be ignored. So shouldn't we be embracing this new form of output and encouraging printing? 

Pinky - you left the lens cap of your mind on again.