Well, I didn't do a "full web survey", nor do I have time for one either. I just wondered why some people keep bringing up that Libby pumpkins weren't pumpkins and not showing where they are basing it. I wasn't trying to be all class nerd about it, but I have asked on here before with no answer.
From my not exhaustive "web survey", Libby pumpkins are pumpkins. They are just more closely related to butternut than the pumpkin you buy in the produce section (which are, apparently, more related to summer squash and acorn squash), and are stringless. Which is probably why they are used over other species or cultivars.
When I make homemade pumpkin puree from what we used to call "pie pumpkins", it looks more like Libby's than the stuff in jars.
ETA: Supposedly, the really big pumpkins which win awards are a different species from either and are related to Hubbard and kabochas.