At least you can reuse most of the code thanks to unity support. For any other app, until very recently with react-native, you had to create separate code bases

At least you can reuse most of the code thanks to unity support. For any other app, until very recently with react-native, you had to create separate code bases in totally disparate languages just to target the three major platforms (iOS, web, android). And let's not pretend react-native is a panacea; there's still plenty of work required for cross compatibility especially if you want to use cutting edge features. Walled gardens and market fragmentation drastically increase the cost of app/game development. It's hard for small or single-person dev teams to produce properly multi platform apps. It's sad to think about how much engineering is wasted replicating identical features across platforms, just for the right to play in the walled gardens of our technological overlords.