They have been slowing phasing out finecast. For example the latest Tyranid stuff (Zoans and Vemonthropes) are moving away from finecast (no longer available) and are going to be released in a box as plastics. That said, who really knows. They moved away from metal which was getting more expensive, it seems like finecast was (hopefully) just a stop-gap until they could move everything over to plastics.