Bumping this! This will be my "conclusion post" about mobile stores, I don't think I'll keep "updating" as at this point everything has been shared & learned.
Exiled Kingdoms downloads & sales remain very stable even today, 25 months after release. Sometimes sales begin to decline for a few months and I think "OK, it's over". But eventually they get back to "normal". Likewise they sometimes raise into crazy peaks, and by the time I am wearing my monocle and looking at yatch brochures they once more drop down to reality. But it's a pretty decent reality; in total, combining both stores the game has surpassed 1.05 million downloads (95% from Android). Ratings are improving, with the total average at 4.6/5 and around 40K ratings. The revenue is pretty good, but once you take into account the insane hours invested it's just "OK++". On the other hand, if it remains like this for a long time after development slows down, the return of investment will only improve over the years.
Of course it has to decline at some point. But if games like Pixel Dungeon have reached 5 million downloads, why shouldn't I reach a similar number? I might only have reached a 20% of potential downloads. Or less. Time will tell, I guess!
My conclusion to fellow RPG developers that may read this thread: don't write off the mobile market because of the shitty games already there. The low quality in the stores is actually a plus: a minority of players is hungry for decent games without microtransactions, and you'll likely have much less competition than on PC. Sure, 90% of the Play Store users will not like an old school game, but the other 10% is a lot of people. For years due to work I could not play games on my PC, and the scarcity of decent games on the Play Store opened my eyes. Many modern engines allow you to target mobile platforms, so give it some thought; if your game is good it'll probably be worth the effort to release. If anything, it'll be good marketing for your PC game. Hell, a game like M&M would play fantastic on a touchscreen, the only crawler in the Store is "the Quest", and I purchased it at 9 bucks.
Aside from the thread main topic: From now on I'll focus all my efforts on PC development for the next years. I just completed the PC version of EK, which is already "coming soon" on Steam and will be released next week; it's getting a lot of wishlisting so I hope it sells well. Then comes my next RPG which I think I can develop without pressure, crowdfunding or anything of the sort (or so I hope!). However, EK will still take some of my time in the next months (or more) as I want to add a little more content and features; it is the least I can do for the incredible community that supported the game, tested it professionally, wrote a full wiki, and even fully translated it to several languages. More EK development is not something I look forward to after 4 years of looking at the same code, heh. But I can't just abandon the playerbase while it's so crazily active. This is especially true if the Steam launch works well, it'd be good to give the new players a few updates as well. Still, the next game should have 60-70% of my time, and I hope to be writing about it soon.