>>720189954
The actual answer is monetization both through advertisements and in game purchases.
There was a short couple years from around 2007 - 2010 where mobile games were actually alright because for many games were only buy to play, you spend 3 bucks and you got a JRPG.
There was no freemium, no buy to block ads, no subscription services or season passes or in game ads and purchases or premium currencies or anything like that.
Then suddenly there were and the mobile game sector started to explode. In 2010 mobile game market was $5.6 billion in, a 19% increase from 2009 revenue of $4.7 billion. 2015 ive years later the value was $39 billion. 2020 5 years after that it was $121 Billion, this year it will be over $170 Billion.