So, I get why NeoGAF would shrug at this, but any anger over this not being for you is pretty silly. It's different teams (often different companies) making mobile product, it has the potential to make a lot of profit for Bethesda (which gives them breathing room to not rush other projects,) and Fallout Shelter was a fun mobile title (and also had some console versions.)
Relax, you'll get the next real Elder Scrolls with or without people who are not you enjoying Castles (...if it's good.) And you won't get it any faster if there's no mobile spin-off game. (You also probably won't get updates on Elder Scrolls 6 for... well, just don't hold your breath or get into a tizzy every time the words "Elder Scrolls" shows up on a forum.)