WPF was abandoned at birth, it went years without any attention and then was superseded.

Apple has at least been consistent on UI frameworks.

WPF was stamped out by lack of dogfooding = inability to inspire confidence, and then Microsoft spazzing out with that clusterfuck that was the Windows 8 "Metro" bullshit.

Back when I wanted WPF to succeed, Microsoft was barely using it in any of their own apps.

Apple has used SwiftUI in their OS more than MS/Windows did, and there's quite a few apps on the App Store that -seem- to be made with SwiftUI.