There is a problem marketing this movie for a few main reasons:
1. No A-list lead actor to attach it to. You guys can talk about actor A-B-C all you want and how good they are. But the reality is an A-list actor is statistically proven to attract a percentage of money, just on the name alone to a film and that alone will pay for the marketing. The marketing will be minimal on this film. So we need to get used to it. Please understand the "term" marketing isn't just previews. It's a guest appearance on a Late Show, it's a tied in promo with the Wax Museum where Actor A plays a wax figure, it's filmed put on youtube everyone see's, laughs, loves. ETC. Pitching Boyd Hollbrook to appear on SNL, or the Late Show or a Wax Museum isn't putting a dent in anything. No knock on Boyd or the crew, just isnt'.
2. It's Niche. Because of the prior failures of this film franchise (Prometheus is also used as a gauge here, same fanbase) and the landscape and the fact that this film isn't slated for the "summer blockbuster" talk. Movie writers/critics aren't writing about this film, will be alls quiet until release. It's slated for Sept, the "wind down time" in the industry (again you can pretend that the whole "IT" phenomena will permeate to Pred, but your pretending, it was a perfect storm aka phenomena, so that "reasoning" is a pacifier the FOX big wigs are feeding you). Right now it's not on the radar for "mainstream" promotion.
3. Movie money is the lowest it's been in 20 plus years. People are going to movies, but not as often. So Family A, or person A, isn't going to see 5-7 movies in a span of May thru Dec. They will now see 2-3. So they are planning Jurassic Park, Avengers and DeadPool. They aren't going to budget for 3-4 more obscure less known films. They will see the "big dog" movies and be done. And that's just a fact.
So while the fanbase for this film is rabid, we need to realize that the rest of the world likely hasn't heard a peep and if they did, don't care for the reasons stated above.