I don't know that they're running in quantities that high, but definitely in the thousands. How? poor quality wood in razor thin veneers. While Dingwall tops aren't think, I would think that a single Dingwall top would be 5+ tops for some of those other manufacturers.
You know, I see all these pictures low end production basses with fancy tops, and they look nice in pictures. Then you see them close up. And they look terrible. They don't 'move', they don't have the same 3-D that a real one does, they lack the way that light is captured by good wood grain, etc. In many cases, the lower end ones aren't really even wood...they're like the old fotoflame MIJ Fenders that people tooled on back when they came out.
Also, a lot of the tops you see in those basses are 'maple' but what kind, etc. Most maple isn't rare, hard to find, etc. It's readily farmed and available. I think that furniture production probably takes a greater toll than luthierie.
But yes, the reality is that there are guys out in fields, looking for the rare, looking for burls, and for hard to find species...and it would be great if they could be stopped, but then people are still killing elephants for tusks, and rhinos and turtles...the list goes on and on. Trees don't move as quickly...