The accumulation of things (including sewing machines) can be a burden on one's spirit after a point. That point is at a different number for different people. I don't advocate taking a sledge hammer to a good machine -- that is disrespectful. However, if I can't fix it, and if it cost nearly nothing in the first place, then I will think long and hard before spending much money on it. And I sure don't want to have to store it in unworkable condition. That is when it is given to someone who can do something with it or it is parted out.
Just me. Maybe my spirit needs adjusting!