Thingiverse IS a Makerbot creation anyway. My opinion is they understand most people don't have CAD skills and they intend to alleviate that.
But people will soon see that there is a huge difference between a 3d model and a 3d printable model.
Also, there is so much it is getting a bit unwieldy. More work to organize ans check the stuff ? But in that case can it remain free ? We'll see.