The 5012 Ingersoll is a re-badged Grazer ZTR. I'm not sure if ZTR's are classified as being a "tractor" in most people's eyes. The newest that unit can be is 2004 because production stopped at that time. I suspect that the 4020 is of the same vintage.
If I am right, then these machines have sat unsold for the past 8 years or more. And the owners have had their capital tied up in them all this time.
You don't mention prices but again...I suspect that the prices have always been more than the local traffic would bear and that's why they remain unsold to this day. Old School or not, keeping iron on your showroom floor for all that time is called poor business practice.
Eventually, this business will shut down and these units will end up in the liquidation auction to be sold for chump change compared to what the MSRP was when they were new.