By the time our mathematical little friend here figures out what he is doing, do you really think people are going to still be using WinForms?
In short, yes. It's quick, stable and apparently MS is going to keep supporting it although it receives next to no new features. You don't have to screw around with XAML and the full framework is available to you (as opposed to "metro" apps). It's clearly not MS's direction, but yes, people will still be using it.