Apple's answer to the struggles of premium mobile titles, Apple Arcade, may have already managed to accelerate the decline of such titles not on its service, though said decline was already chugging well along on its own.
Sensor Tower reports that paid game revenue on the App Store declined 13% from the period of August 20 through September 18 this year to September 19 through October 18 -- Apple Arcade's launch month. Some of that decline can be accounted for by a normal seasonal drop, though the decline over the same period last year was only 4%.
That's still a significant difference, but it may also be attributed at least in part to the ongoing decline of premium titles on the whole, a process that's been steady since 2015. Per Sensor Tower's findings, premium games have grossed a total of $337 million on the App Store year-to-date as of September 30, which is less than 2% of all App Store revenue. That number was much higher in 2015, with full-year paid game revenue totals reaching nearly $642 million -- 5.4% of all revenue. Apple Arcade would need approximately 11.7 million subscribers paying for 11 months (after the one-month free trial) to equal the amount of money generated by paid games on the App Store in 2015.
In fact, free game revenue has increased each year from 2014 through 2018, while premium game revenue has declined both in dollar amount and share of all revenue since 2015. So have new game releases, with paid game releases on the App Store going from 26% of all new releases in 2014 to 7% of new releases so far in 2019. Currently, nearly 13% of all App Store games are paid.