Why? A publishers goal is always to pay nothing at all for the rights, at best this is simply another excuse.
For the same reason a 35-year lease on a house is cheaper than buying it outright. If you know you won't own it forever, you won't pay as much.
alt Hacker News
For the same reason a 35-year lease on a house is cheaper than buying it outright. If you know you won't own it forever, you won't pay as much.