That "finite number" may well be over a billion. If you look at Singer documents, millions of machines were cranked out every year. And they were made to last forever and they will unless left out in the backyard to rust. Never fear, there will always be PLENTY of old Singers around... for the rest of our lifetimes. We love them and seek them out because they are part of our history-- we learned to sew on one, or Grandma had this other one.... The current generation did not grow up with those old machines (for the most part), so as Patrice mentioned, they will not value or demand them.
Cari, if you are lacking in old Singers, please come to my house and take some home!