At least since whe know the (very cheap) price tag for arcade (and TV+) it should be clear that the main intention is to push <DEVICES> + to push the over all quality of appstore&itunes content. Content & App quality is a main reason why non apple fanatics are buying apple stuff. The second intention is to reduce the huge amount of low quality p2w games, which are one of the reasons, that many gamers don???t play games anymore (and keep their devices, especially iPads for ~5 years, instead of buying a new iPad Pro every christmas).
The knew exactly that iAPs reduced/killed the quality, kreativity and fun to play 90 percent of the mobile games. The earned much money from it, but over the time selling devices (and defending the market against huawei&co) is much more important than earning 30% from crystals and chests. They need to sell more devices, they need to defend the iPhone market against China and the iPad market against Microsoft and they need to dont loose the home market completely against consoles and android dominated alternative home media devices and Smart TV Games.