Read this interview of Brad Sams with Richard Kerris at Neowin
When it comes to developing for the Lumia series, or Windows Phone 7, Nokia is far from calling the system dead. Not even close, with 7.8 and other enhancements in the pipe, the product line is as vibrant as ever. Additionally, Kerris states that what Nokia is doing is no different than what Apple has done with the iPhone 4S and iPhone 4 with Siri.
Kerris states that the developers he has talked to want to target the millions in the install base with Lumia devices and that they will receive the added benefit that their applications will work on Windows Phone 8. [...]