They don't have to scrap anything....
As this pertains to Whirlpool Belt-Drives and Direct Drives, the appliance stores simply choose to scrap the machines because they are heavy and bring some decent money for scrap value. That coupled with harder to get parts, know-how that may be lacking in some cases where the techs are all geared for DDs and other more recent designs, these shops simply don't want to work on the old machines or have any connection to them after the sale. Its not a case that they can't or are prohibited.
If there were environmental issues, the DDs would be in the same situation because a Belt Drive doesn't use much more water if any than a DD with the exception of the 2011 compliant DDs.
Most appliance stores that I know of, both in this area and out west where some of my machines have come from, have been passing on BDs, most Filter Flos, and others of that generation simply due to their age.
Gordon