You fail to understand that Space Marines are their cash monkey for 40K. As long as they are their best selling army, they are going to continue getting the Lion's share of releases.
As for Fantasy, they have already announced the release of two armies for this year and there is only 2 months between them. That seems pretty fast to me. There definitely are armies in Fantasy that need updated models though. I can't say I'm upset that the Empire got some new stuff though, this is a website devoted to Empire so that shouldn't come as a surprise. If the rumors are to be believed, the Tomb Kings will unfortunately not be getting any new skeletons, which is sad as they really need an update.