David Bowie may have developed the so-called "Stage Fright", and this would be the reason for the musician to be reluctant to return to the stage. Bowie has not performed live show since July 2004, and "The Next Day" is his first album of new material in decade, since Reality (2003).
The British newspaper Evening Standard published an article stating that Bowie received millions of proposals to perform in London next year, but so far all requests were denied.
The idea of Bowie being afraid to perform live is not without some irony. After the singer is one of the most responsible for developing the idea of show as spectacle, as used today by names of rock and pop. A pioneering example of this can be seen in "Ziggy Stardust "1973 below: