Earlier quoted context omitted.
With this approach, your novel becomes an average of what the masses like to read, rather than what you wanted to say. Engineered for the masses, so to speak. Which, of course, could explain why King is so successful.
IMO, this is an artistic fallacy that needs to die. Responding and adjusting to feedback doesn't undermine the integrity of a work or weaken its authenticity. Cycles of feedback and iteration are common to all work in every medium. Obviously, you can take responding to feedback too far, but the idea of the artist-in-a-tower-birthing-a-fully-grown-work-whole is an inaccurate idea at best, and a damaging assumption at…
One place to get feedback is in writer's groups/clubs. They may not reflect your intended audience as much, but they're also writers and would be better at separating their subjective biases (like not liking sci-fi) from a more objective analysis of the work, looking at things that are common to all writing, esp. fiction (is the writing overly wordy, does the plot make sense, are the characters believable, etc.).