The problem is that Mobile has a very fast development cycle in Japan. I asked someone who lives there and plays a lot of the social media games, and apparently there are hundreds of them that come out every year, and displace previous games in the series. They're literately designed to milk whales for all they got.
http://reboundmobile.com/more-than-1...onths-of-2017/
https://mmos.com/news/japanese-playe...ame-no-regrets
My personal opinion is that the mobile market has a lifecycle that goes with the device replacement schedule. You get 2 years out of the hardware, and 2 years out of the software. This is largely because the developer has to keep supporting old devices, and Android devices are super-expensive to keep supporting as there's many rubbish ones. All the money to be made in mobile is on the iOS platform. Korea gets more life out of their mobile devices largely because Samsung and LG are their native manufacturers, so it would be a bit off-putting if they don't support their home market developers. Apple is entirely "do it our way, or you're dropped from the store", with developers deciding to drop microtransaction games from the store early that aren't profitable enough.
I really hate how microtransactions have utterly ruined games for that platform and have creeped into desktop/console games. Sure a developer is free to do whatever they want to make it worth developing the game in the first place, but some developers seem intent on a repeat of the games crash of 1983 by pushing out as much crappy, time-wasting-if-you-don't-pay-through-the-nose, games as possible.