I agree with you. If you read a disappointing book, then you're less likely to read any more by the same author.
For that reason I'm not a fan of Michael Moorcock. Back in the 60s, he wrote a trilogy that plagarised Edgar Rice Burroughs Mars books. I upset some of his fans about this back in the early 80s but he agreed with me that he had to make some money for his New Worlds mag but it took the wind from their sails. Even so, its one thing to take a scenario someone else used but not to do things your own way is asking for trouble.
Other authors who've plagarised tend not to sell again but this blemish in Moorcock's career seems to have been glossed over. My own contension is if an author has done it once then they're likely to do it again.
The problem with William Gibson's cyberpunk novels that always struck me was how could he think anyone who was stoned on drugs could write computer programmes.