Training companies, for instance, will do the hard work of helping Bryan move his apps to WinFX. It won't be easy. If you watch the Sparkle video you'll see that the entire architecture and development process for building these new apps has changed from the VB 6.0 world. That's why Microsoft hasn't built a porting application yet. Just like there weren't good porting apps from Apple II to Macintosh apps. Or why there weren't good porting apps from DOS to Windows. Or why there aren't good porting apps that'll take you from a Windows app to a Web Services app.
He's making the claim that an application's architecture has to change when moving from VB6 and (insert any version of Windows here) to WinFX? Say what? It's one thing if that "port" means moving from fat client to server based - in that case, yes - the architecture has to change. I had to explain that to people multiple times back in the late 90's, when they wanted to pick up VisualWave and do an insta-port to the web. The basic issue - single user vs. multi-user.
But there are plenty of apps that aren't going to go that way. Not every application needs to support the WS* stack, and plenty of apps are just fine (architecturally speaking) as they exist now.
When someone says "you'll have to buy training and use a new architecture" in order to run your application on a new OS, one of two things is happening: either a non-techie who barely understands "application architecture" is speaking, or you are being sold a pile of crap. Possibly both, I suppose. With Scoble, I suspect it's the former - he's not dishonest.