Been gone from this site for a while, just got done reading this entire thread with great interest. There are a lot of good points being made here. I think I can add a few things to this discussion:

I describe Thingiverse as the "youtube" of 3D to my customers. Very similar in a lot of ways. Unlike Youtube, obviously Thingiverse exists primarily to drive business to Makerbot. They spend a lot of money paying software engineers to build the code that runs the site and host all the content. That's not free by any stretch. But essentially their advertising is all Makerbot.

We carry 4 different brands of 3D printers in our store. The Makerbots are clearly superior to the Type As and Lulzbots in build quality, and the combination of Makerware slicing and Sailfish firmware yield the fastest builds of any of our Printers. The only one that comes close is our ZMorphs running Voxelizer. I attribute the Makerbot performance superiority to being closed source, and having the resources to pay a lot of top-notch engineers, not to mention access to Stratasys' expertise, which brings me to...

Bre stated in an interview not long after the acquisition that he "allowed" Makerbot to be acquired primarily to have access to Stratasys' patent portfolio. No idea if that is true, but I did watch him say that in a video of the interview.

As for these "Behemoth" companies raking in all this money, um....latest results for SSYS shows a $(0.20)/share loss and while DDD is technically making money at $0.43/share, they're trading at !!!130!!! times earnings. Their gross margin is less than 10% - not exactly raking it in.

Finally, Thingiverse HAS started charging. Recently they came out with a T-Rex skull and jaw you could download and print for free...and if you want the rest of the animal's bones you have to cough up $15 USD. I haven't checked but I saw somewhere that not only that, but the bones are ONLY in X3G format, which of course means you can only print them on a Makerbot. I may still pay for them, the skull and jaw are way cool! We have a full sized build on display in our store and have 1/2 sized ones on our free sample table.