It's interesting, I saw an ad for his new album last week and though I knew he was in his late 60s I wasn't surprised, my thought was more like "of course he's making new albums." That's just how he was.
When I was in high school, the "new wave" kids would listen to early Bowie records, even though they were "rock" and they would never consider listening to something else that came out of the same scene like, say, Mott the Hoople. Very few people have managed to successfully combine, bridge and transcend so many pop music genres. He was very, very smart about his career, how to present himself and how to anticipate -- and sometimes influence -- trends and fashions. He was so prolific for so many years, it was inevitable that he would make some bad records. But hit or miss, I have to respect his fairly unlimited expressive vision.
I also respect that he kept his illness private, and didn't become the subject of some kind of "death watch." One final album and out. One of the greatest, gone.