Apple's approach seems to be to use Swift packages as an alternative project type that can be shared across iPads and Macs and, most importantly, do not require support for running binaries outside of an app container.

How this evolves over time depends on Apple's opinions about their operating systems. If they were to basically hand people what amounts to a manufacturer-sanctioned jailbreak, then they could port Xcode to UIKit with all the functionality it has on MacOS, save for the lack of AppKit support. Alternatively, and more likely, what they'll do is add new app extension types to do Xcode-like things in Swift Playgrounds. So if you need to, say, use Rust code in your app; you'd literally download a Rust compiler from the App Store to do that.

Or they could do nothing and be satisfied with the hobbyist-grade, Swift-only programming environment they already ship.