They have to, they didn't get this brand. They've just got rights to use it for few years together with mobile devices part of Nokia.
Microsoft bought devices and services and right for Nokia name for few years. I think they need to drop Nokia name from new devices.
Someone saw me using my Nokia on the train the other day and commended me on Nokia's record with labor and child labor in particular.
How is the brand valuable in a practical sense? On the other hand, it has plenty of negative association as a company that tried and failed to compete with Samsung and Apple.