This is what I think will happen. I think That Marvel will publish an Alien Romulus art book. Firstly, the release of the art material has been very consistently staggered and controlled. So there appears to be some sort of coordination afoot to keep the fans interested. To what end?
Secondly, Marvel has published many art books long after films or tv series have come out. A good example is Hawkeye. The art book came out many months after the series. Is there anyone that believes Hawkeye gets an art book but not Alien Dimulus?
Also, thirdly, Titan isn't talking about an art book so it doesn't appear to be in their radar. You could be sure that they would have spoken about it if it was going to happen. I think they e been instructed to stay silent about it.