Why aren't there more turn-based RPGs or tactics games like Advance Wars?
There are. There are thousands of them on the app store with new ones released every week. Some are paid, some are totally free and some have iap. They all just disappear into obscurity.
The problem is the people who play games on mobile devices are not gamers. They are housewives, teachers, politicians. The same people who will watch you play GTA, COD or Skyrim and mutter that they just don't get it.
The truth is on smartphone there is no point trying to make a good game. The only thing that you will earn by designing and developing good original games on mobile is kudos and respect from other developers. As for money forget it the way to go is clones and huge volumes of games that you can knock together in a week.