He only has 400,0789,036 elves left as he just fired 63 of them for slovenly workmanship. Santa is a hard taskmaster and will not brook any sloppy work.
Research shows he has an unlimited amount of elves. The more toys there are to make the more elves there are to make them. And they leave when they are finished making toys.
You do know that Santa does not pay the Elves for the work that they do. So they come and go like fleas on a dog.