Probably WB set a date for it already and NRS has no power to change that. At least that's what I'm thinking.
Exactly, this whole discussion is a little bit odd to me, it's pretty obvious the marketing team is an outsourced solution that supposedly is specialized and responsible for the reveals and the materials related to it.
Likely the marketing company believes the best way to generate hype is by leaving people with nothing for a while, and indeed people ARE talking extensively because there's a lot to especulate and nothing is certain. Well, nothing was certain.
Also consider MK has a very casual oriented player base, people that believe DLC should not be released all the time. Imagine NRS announced KP3 the month after Aftermath, this would definitely not go well, they just charged for an expensive pack and there's already another product to look out for. We would be happy sure, but people are dellusional if the marketing company is gonna look at the fans and not the vast majority of the MK consumers when it comes to pacing their reveals.
Keep in mind that MK doesn't follow the same business and reveal format from SF or other fighting games for a reason, and it's a business one. That's part of how they make it to 5th best seller of the year.