I think it's simpler than that.
Miramax, a joint producer for the new film that's owned by Disney, likely didn't want to play in granting rights.
Universal Marketing (and A&D) would have clamored for the new film. It's more relevant and a bigger deal. However, this house was ALSO a late addition (that's why it's in Shrek, which was supposed be demoed this summer). So, any hold-up on rights would have an outsized impact because timing was critical. And Miramax is the most likely culprit.
It's not about the event's theme. They don't go in at the beginning of the year and say "This year's theme is ______." This year is a bit more organic, but there's some glaring exemptions from the "Horrors from the Past" theme they're going for. Blumhouse, for one, and the originals apart from Sinema only fit because we're being told they fit (think about it - all of the originals would be just as fitting without a "theme").
Oh! I hadn’t even considered that the film was part produced by Miramax. I also think it’s hilarious that they do Scream, which also has had a lot of trouble at the event.
And while obviously the year’s theme is broken by Blumhouse, I think they did a very good job adapting the other houses to the theme, and marketing for sure pushed it along. Of course the other houses could easily take place during other years, but I think there are some good cases to be made for at least 8 of the houses being of the 80s:
WARNING - HEADCANON
1980 - Slaughter Sinemas (Indicative of films in the early 80s)
1981 - Carnival Graveyard (Similar to films like “The Funhouse”, which came out on that year.)
1982 - Poltergeist
1983 - Stranger Things
1984 - Trick ‘r’ Treat could be slotted here - it could take place any time due to it’s comic book style, but it fills a gap. Apparently 1984 wasn’t such a scary year.
1985 - Scary Tales (While not officially part of the house, Return to Oz came out this year, which is a pretty horrifying re-imagining of The Wizard Of Oz in it’s own right...)
1986 - Seeds Of Extinction (Chernobyl)
1987 - Uhh. We can throw Blumhouse in here. In 30 years, the First Purge would take place.
1988 - Halloween 4, Killer Klowns, Child’s Play
1989 - Dead Exposure (The AIDS Epidemic; Haemophilus Influenzae Type B Vaccine widely recommended)