It can't be the only reason, since Gregory McDonald kept two in parallel in his (rather short length) Fletch mysteries, while Philip K. Dick tended to use three plot threads, sort of like the Love Boat, in his (rather short length) SF. But it might be a contributing factor.
no subject
It can't be the only reason, since Gregory McDonald kept two in parallel in his (rather short length) Fletch mysteries, while Philip K. Dick tended to use three plot threads, sort of like the Love Boat, in his (rather short length) SF. But it might be a contributing factor.