The dungeon habitat was released several YEARS ago and the mobile app has always said it will be "supported in the future." How many years in the future are they planning to finally make it available on the mobile app?

I assume you are referring to the floating dungeon hab? Honestly I doubt it will ever be supported in the the future. I have just put my lowest dark earners in mine so I will not miss collecting the gold for them.

BTW this is not a bug, just a feature they never implemented on mobile, moving this from the bug section.