It is greed. The guys professionally parting tractors are avoiding the liability of selling a complete machine.
Maybe greed for some, but most of these guys are simply scraping by a living just like you & I. And as far as the liability of a whole machine....that's not their fault but the buyers. Many of these guys have been talked into selling a tractor whole, and is an "as-is" deal, only to be hounded afterwards because something went wrong and they want their money back, or it to be fixed for free. So many people just don't get the "as-is where is" with used stuff. It is way too much headache for them to sell complete tractors, and they should not be blamed for that.
How many of you have sold a car or similar & the buyer come back complaining of this & that, when they accepted the car or whatever "as-is"?