I think you answered your own question—the marketing department might be intentionally trying not to spoil too much for the viewers. Perhaps they want viewers to focus on Cosmog's and the Aether Foundation's upcoming debut (which is a big deal). Perhaps they want to hide an upcoming evolution.
I don't know why a lack of information leads you to assume the marketing department doesn't care about Sun&Moon or that Sun&Moon promotion has been awful. Withholding information can be just as effective a marketing tactic as revealing information. The marketing department has revealed what they want viewers to know and/or focus on, and has withheld what they don't want viewers to know and/or focus on.
Honestly, I think many fans have been spoiled by the tendency of magazines and other promotional materials to spoil upcoming episode titles, to the point that they feel entitled to a deluge of information.
Intentionally hiding summaries, or detailed information is one thing, completely hiding titles is an entirely different thing.
To me, not revealing information as such titles, to me shows they don't care about the show, because its like the SHOW doesn't even exist.
How can viewers tune in to the next episode, if as far as they are concerned there is NO next episode, how can people organize the schedule to be able to sit down and watch a 20 minute show if as far as they are concerned there is no episode.
"Well it doesn't look like there's an episode on October 12 or 19th, I guess I'll go on that two week date with that person I've always gone with."
Even with titles they could better gauge if they even want to watch it when it airs, or they could hold off on.
No casual (and casual being the primary word here) viewer should be patient enough to want to wait until information is revealed.
In America, changing the days of television show, to a different day often spells disaster because people would have to reorganize their entire schedule to watch THEIR show, and they likely do it for some instances because of the viewership during that time frame, which MIGHT be good for the new show, but might be bad for the older show.
Don't think that's necessarily a problem for Pokemon or Japan but I would think LACK of information would most definitely kill off casual viewers because they can't come up with a consistent schedules if they don't KNOW anything.
Even I, who doesn't qualify as a normal or casual viewer is feeling the strain of lack of information, and even though there's no reason, I almost feel like giving up on the sun and moon anime, because it seems like they don't care about the series. Lack of information naturally and logically kills any sort of media. Movies with lack of information ends up not doing so well when its released, and bad movies with lots of promotion tend to do better than they should.
Hiding the Cosmog storyline was annoying but clever, at this point I don't care about the "Clever" aspect since its been done before, now I "need" information to flow in order for me to think they actually care. It most definitely now especially feels like they are pumping out an episode a week for the sake of an episode a week regardless if its an amazing episode/plot.
Everyone is different, so agree to disagree I guess.