>WPF on the other hand hasn't had a major change since 2006.
WPF (v1 not beta) was released November 2006. I'm sure that at that moment in time, Microsoft did have optimistic visions that WPF would be widely adopted like Winforms and VB6 Forms before. In 2006, WPF was prominent in MS's strategy. But by 2012, it' wasn't.
What changed Microsoft's direction? What did Microsoft not know in 2006? What they didn't know was that 2 months later, Steve Jobs would show the first iPhone. That changed everything.
Before the iPhone in 2007:
- Research In Motion and Google's Android (1st prototype) thought smartphones would be half-screen, half-buttons.
- "fat clients" with rich runtime plugins like Adobe Flash and MS Silverlight would be dominant
- there was no significant application development & distribution platform on mobile phones (yes, Nokia had a SDK, and Microsoft had something for Windows CE but neither gained any significant mindshare)
If we look at the macro trend, the ongoing investment in WPF assumed that desktop apps would be dominant in developer mindshare (either Silverlight or traditional desktop exe files). With the rise of iPhones/Android, it was HTML5 & Javscript that was aggressively enhancing their capabilities. The rising marketshare of Google's Chrome (2008) with the V8 Engine and Mozilla Firefox improving their Javascript performance also contributed to WPF's abandonment. For native apps on smartphones, developers en masse were more interested in Apple Objective-C or Android Java. HTML5+JS+ObjC+Java all gained mindshare at WPF's expense.
Microsoft didn't instantly declare WPF "dead" in 2007 but abandoned it in gradual steps. E.g. the conferences PDC2009, PDC2010 had prominent WPF presentations but the later Build conferences do not. It also didn't help that the first WPF release didn't have masked-edit controls, didn't have a datagrid, and didn't have a good UI designer (Expression Blend purchased separately?). VB6 in 1995 had masked-edit controls but WPF didn't?!? WPF was also very slow even though they touted the underlying DirectX technology. (E.g. Evernote abandoned WPF for C++ WTL.)
If you're a developer that wants to code a brand new WPF application today, that's ok but don't expect MS to release new exciting enhancements for it.
Today, innovation iteration on desktop GUI libraries are happening faster on Qt for C++ and React/Electron for Javascript.