With advent of WPF and MVVM Microsoft introduced
INotifyPropertyChange interface to provide a way to implement the "reactive" approach used with those technologies.
Sadly both of these constructs are very verbose, require much boilerplate, are clumsy to use, also are not really that safe since they require much use of "magic strings".
So here come the question: why didn't they put these functionalities directly into the language - why didn't they create new kind of properties created with a simple keyword, providing useful stuff of
DependencyProperties (like events on change and so on...).
What were stopping them?