Nor would his publisher have the right to retitle it "Blade Runner", most likely.
Scott was looking for a cooler and more threatening name than "detective" to call Deckard and his unit, and eventually bought the rights to the name Blade Runner, taken from the '79 short novel Blade Runner (a movie) by William S. Burroughs. Burroughs loved Dick's work, and was pleased to sell the name. Scott loved it enough that eventually he used it as the movie's title as well.
The Burroughs novel is good - and it is also SF, but has nothing to do with the movie or the Dick novella Scott and co. loosely adapted. In WSB's novel, a blade runner is a black market runner of medical supplies.