Best answer: Minecraft Dungeons breaks Mojang's tradition of bringing Minecraft to mobile, with the release being kept to gaming consoles and PC's. Dungeons, with its upgraded graphics, complex playing mechanics, and busy HUD, just isn't a good fit for small mobile devices, so it didn't make sense to make the jump. That doesn't stop Dungeons from being available on all of your other favorite gaming platforms, however.
Full story from the WindowsCentral blog...