If you listen to the last album you could interpret it as goodbye.
Dies on his terms hence the veil of secrecy.
When he was recording The Next Day, there were only 30 people in the world who knew about it. Receptionists were given days off, album recorded at weekends etc.
Tony Visconti his acclaimed producer had the rough cut on his iPod and was walking in The Village NYC, and walked past two Bowie fans in Ziggy t shirts.
If only they knew what he was listening to!
Died as he lived, on his terms, in secrecy
Rest in peace, and thank you.