The set that was used to film the Hulk's final scene initially remained intact because of plans for a fourth post-series "Hulk" TV-movie (which had two working titles: "Rebirth of the Incredible Hulk" and "Revenge of the Incredible Hulk"). However, Bill Bixby's death prevented the proposed installment from being made.
While Bill Bixby's terminal health is cited as the factor for postponing and ultimately scrapping a follow up movie that was not the case. The decision was made prior to Bixby's health becoming an issue, and was based on ratings declines by the film series.
After the ratings failure of this film, NBC decided not to continue the series. CBS already wanted nothing to do with The Incredible Hulk, prior to The Incredible Hulk Returns (1989), so for the planned next installment, first Bill Bixby tried to reach an agreement with ABC and they turned him down, then he did the same for the Fox Network, who agreed to air another movie. Bixby and Fox were doing business together, until Bixby was diagnosed with prostate cancer, causing production with Bixby and the network shut down.