I used to think like this before I saw companies like Instagram and Tiktok thrive in the app store, which they absolutely cannot control. It is often worth a shot.
Relying on the App Store to distribute your app is more than a little different than building an extension to iMessages. Apple and Google want you to use their app stores in this way. Apple does not want you to bridge iMessages to other platforms.
It’s impossible to avoid relying on other people’s platforms. (Unless you want approximately zero customers, I guess) I wish these monopolistic corps didn’t have such an iron grip, but I’m not demanding creators single handedly remove every dependency on them. There is no ethical consumption (or production) in late stage capitalism.
