Microsoft has a long history of releasing numerous UI frameworks: VB, MFC, WTL, Silverlight, WPF, WinForms, and others. Yet despite this abundance, many of the core components Microsoft used in its own applications were never available to developers. They rarely ate their own dog food, and desktop UI development relied on third party components. For the past two decades, native desktop UIs have steadily declined in favor of web-based components, so it's unclear what the real benefit of another native framework would be today.