You can almost understand Universal's hesitation to revisit the Hulk on film: Hulk movies aren't the shining example of how to make a good superhero movie. If there's one blip in the MCU, it's Edward Norton's The Incredible Hulk movie, which ironically featured a villain called the Abomination.
It's possible Universal feels there are no more Hulk stories to tell. But if that's the mentality, that just means they don't have any comic-book people over there.
If Universal had executives who really cared about the characters, or a passionate director like, say, Wonder Woman's Patty Jenkins, they'd realise there are a lot of potential options for a movie.
A piece to the Hulk moviemaking puzzle is there waiting in the MCU: William Hurt's Thaddeus Ross, Marvel Studios' military man, who resurfaced as secretary of state in 2016's Captain America: Civil War. And since the Planet Hulk comic-book story line has already been used in Thor: Ragnarok, why not revisit one of the next best Hulk tales out there for a movie adaptation: the Red Hulk?
The Red Hulk is stronger, and he retains his intelligence when he "hulks out". His secret identity? Thaddeus Ross, who has always hated the green Hulk and Bruce Banner equally. How great would it be seeing the Hulk going up against the Rulk? The gray Hulk could work, too: He's not as strong, but the much more intelligent Hulk appeared in Marvel Comics during the 1980s.
Everything is there to help the Hulk start smashing at the box office all by himself. But if a solo Hulk movie is never meant to happen again, at least we have the Revengers ... I mean, Avengers ... movies.