Why did Microsoft acquire Xamarin?

The better open source option existed. You always see people ask if WPF will eventually run on Linux, but you can. Just use E-Face XAML for Java on Mono-Java and make jar to C# Dll for mono. Or similar options. Yes, Java is supported by IKVM.Net in Mono. There is No need of so many troubles of learning Xamarin which is not so great… At least, your WPF doesn’t need Change and can run well on other platforms. If not well enough, MS could only pour money to improve code and performance..