Star Trek IV The Voyage Home is the most pivotal installment in the entire Star Trek franchise. Let’s step back in 1986 for a moment. At this point, Star Trek simply a cult phenomenon that sprouted a couple moderately successful movies. The first three Star Trek movies were hits, but they weren’t HITS like Indiana Jones, or Ghostbusters or Star Wars, at least financially speaking. Despite having been in the mainstream public for 20 years, Star Trek was still struggling to attract mainstream movie-goers. That of course changed with Star Trek IV, which won over mainstream audiences.
Why is any of that important? Because the next phase of Star Trek starting with The Next Generation stemmed from the financial success of Star Trek IV. Paramount CBS Television pushed forward with their new Star Trek show because Star Trek IV’s financial success gave them the confidence to finance what would become The Next Generation. Had TNG never materialized, there wouldn’t have been Deep Space Nine, Voyager, Enterprise or any of the TNG movies. I know, I know. A lot of that was really bad, but it kept the franchise alive and in the public eye. If the 24th Century Rick Berman Star Trek never happened, the franchise would’ve likely petered out when The Original Series movies ended.
Another franchise-altering thing to come out of Star Trek IV was William Shatner’s clause to direct Star Trek V. That clause was negotiated when he signed on to star in Star Trek IV. That means, during the entire production and the period following the film’s release, Shatner already knew he going to run the show for the next movie. When Star Trek IV became a massive financial success, Shatner and the rest of the production team had to have been cognizant that Star Trek V could attract even larger crowds.