Not that many people on Android are willing to pay $60 for an app.
https://dontkillmyapp.com/ is just one example of the kind of problems app developers face on Android
Like GP, I'm also a paid subscriber and I couldn't care less where else it's available. If anything, it being a native app rather than a multiplatform JS wrapper is a plus to me.
Those platforms don't generate revenue
BTW, them being iOS-only means they're probably getting lots of marketing support from Apple and other perks. That can really help a startup.