I agree that Android has greater potential, though. Just pointing out that Objective-C is cross-platform, though the open-source GNUstep framework.
Who else uses Objective C in any significant amount? It’s pretty much Apple.
The point is also that with iOS you don’t have a choice BUT to use Objective C. You can’t use alternates.
Devs want freedom. That’s one of the reasons they’re voting for Android as the long-term viable OS to support.