The main means of mobile games gaining revenue is by in-app purchases, and in gacha games like Grand Sphere, Genshin Impact, and Cookie Run to name a few, the main draw is getting all the characters and spending money to get those gacha pulls. Supposedly the drop rates in Grand Sphere are very bad (and I don’t think they have a pity system like Genshin), which just leads to people not really pulling often, a group I was also apart of. But the biggest issue it had was the pricing of those in game currencies for gacha pulls. It cost ten dollars to get the amount of gems you can farm by doing daily tasks and increases from there. Such as spending twenty dollars to get 60 primogems in Genshin Impact (another JRPG gacha game). It’s just not a good deal and most players see that, resulting in very few people buying gems from the in-game store. I believe that, combined with the lack of ads and horrible drop rates led to Grand Sphere’s downfall.