Is XBAP (WPF via webpage) dead?
Xbap is ideal for developing line of business apps for large companies. I used to work in that environment, and ensuring everyone had the correct version of an app was a nightmare.
Unfortunately xbap is late to the party. Most companies have solved this problem with existing technologies (SMS Installers, click once etc), also these companies aren't IT based and don't change/upgrade technologies unless they have to (the IT department I used to work in still use VS2003 and have no plans to upgrade).
So, given the glacial pace these departments adopt "new" technologies, and given their reluctance to change development practises, it could be another 5 or 10 years before they write and deploy an xbap application.
So rather than being dead, I think xbap has a limited audience of late adopters.