Even at their most prolific, a ghostwritten author still probably wouldn't publish more than one or two books a month. Beyond that point, you're just competing

Even at their most prolific, a ghostwritten author still probably wouldn't publish more than one or two books a month. Beyond that point, you're just competing with yourself. (For instance, young adult series like Goosebumps, The Baby-Sitters Club, or Animorphs typically published a book every month or two.) Publishing multiple books per day is out of the question. That's beyond even what's reasonable for an editor to skim through and rubber-stamp.